diff --git a/app/controllers/projects/pages_controller.rb b/app/controllers/projects/pages_controller.rb
index d421b1a8eb5..cae6e2c40b8 100644
--- a/app/controllers/projects/pages_controller.rb
+++ b/app/controllers/projects/pages_controller.rb
@@ -21,4 +21,26 @@ class Projects::PagesController < Projects::ApplicationController
       end
     end
   end
+
+  def update
+    result = Projects::UpdateService.new(@project, current_user, project_params).execute
+
+    respond_to do |format|
+      format.html do
+        if result[:status] == :success
+          flash[:notice] = 'Your changes have been saved'
+        else
+          flash[:alert] = 'Something went wrong on our end'
+        end
+
+        redirect_to project_pages_path(@project)
+      end
+    end
+  end
+
+  private
+
+  def project_params
+    params.require(:project).permit(:pages_https_only)
+  end
 end
diff --git a/app/helpers/projects_helper.rb b/app/helpers/projects_helper.rb
index da9fe734f1c..15f48e43a28 100644
--- a/app/helpers/projects_helper.rb
+++ b/app/helpers/projects_helper.rb
@@ -531,4 +531,22 @@ module ProjectsHelper
   def can_show_last_commit_in_list?(project)
     can?(current_user, :read_cross_project) && project.commit
   end
+
+  def pages_https_only_disabled?
+    !@project.pages_domains.all?(&:https?)
+  end
+
+  def pages_https_only_title
+    return unless pages_https_only_disabled?
+
+    "You must enable HTTPS for all your domains first"
+  end
+
+  def pages_https_only_label_class
+    if pages_https_only_disabled?
+      "list-label disabled"
+    else
+      "list-label"
+    end
+  end
 end
diff --git a/app/models/pages_domain.rb b/app/models/pages_domain.rb
index 588bd50ed77..2e478a24778 100644
--- a/app/models/pages_domain.rb
+++ b/app/models/pages_domain.rb
@@ -6,8 +6,10 @@ class PagesDomain < ActiveRecord::Base
 
   validates :domain, hostname: { allow_numeric_hostname: true }
   validates :domain, uniqueness: { case_sensitive: false }
-  validates :certificate, certificate: true, allow_nil: true, allow_blank: true
-  validates :key, certificate_key: true, allow_nil: true, allow_blank: true
+  validates :certificate, presence: { message: 'must be present if HTTPS-only is enabled' }, if: ->(domain) { domain.project&.pages_https_only? }
+  validates :certificate, certificate: true, if: ->(domain) { domain.certificate.present? }
+  validates :key, presence: { message: 'must be present if HTTPS-only is enabled' }, if: ->(domain) { domain.project&.pages_https_only? }
+  validates :key, certificate_key: true, if: ->(domain) { domain.key.present? }
   validates :verification_code, presence: true, allow_blank: false
 
   validate :validate_pages_domain
@@ -46,6 +48,10 @@ class PagesDomain < ActiveRecord::Base
     !Gitlab::CurrentSettings.pages_domain_verification_enabled? || enabled_until.present?
   end
 
+  def https?
+    certificate.present?
+  end
+
   def to_param
     domain
   end
diff --git a/app/models/project.rb b/app/models/project.rb
index 250680e2a2c..48a81ddb82e 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -267,6 +267,7 @@ class Project < ActiveRecord::Base
   validate :visibility_level_allowed_by_group
   validate :visibility_level_allowed_as_fork
   validate :check_wiki_path_conflict
+  validate :validate_pages_https_only, if: -> { changes.has_key?(:pages_https_only) }
   validates :repository_storage,
     presence: true,
     inclusion: { in: ->(_object) { Gitlab.config.repositories.storages.keys } }
@@ -737,6 +738,26 @@ class Project < ActiveRecord::Base
     end
   end
 
+  def pages_https_only
+    return false unless Gitlab.config.pages.external_https
+
+    super
+  end
+
+  def pages_https_only?
+    return false unless Gitlab.config.pages.external_https
+
+    super
+  end
+
+  def validate_pages_https_only
+    return unless pages_https_only?
+
+    unless pages_domains.all?(&:https?)
+      errors.add(:pages_https_only, "cannot be enabled unless all domains have TLS certificates")
+    end
+  end
+
   def to_param
     if persisted? && errors.include?(:path)
       path_was
diff --git a/app/services/projects/update_pages_configuration_service.rb b/app/services/projects/update_pages_configuration_service.rb
index 52ff64cc938..25017c5cbe3 100644
--- a/app/services/projects/update_pages_configuration_service.rb
+++ b/app/services/projects/update_pages_configuration_service.rb
@@ -18,7 +18,8 @@ module Projects
 
     def pages_config
       {
-        domains: pages_domains_config
+        domains: pages_domains_config,
+        https_only: project.pages_https_only?
       }
     end
 
@@ -27,7 +28,8 @@ module Projects
         {
           domain: domain.domain,
           certificate: domain.certificate,
-          key: domain.key
+          key: domain.key,
+          https_only: project.pages_https_only? && domain.https?
         }
       end
     end
diff --git a/app/services/projects/update_service.rb b/app/services/projects/update_service.rb
index 5f2615a2c01..679f4a9cb62 100644
--- a/app/services/projects/update_service.rb
+++ b/app/services/projects/update_service.rb
@@ -24,6 +24,8 @@ module Projects
           system_hook_service.execute_hooks_for(project, :update)
         end
 
+        update_pages_config if changing_pages_https_only?
+
         success
       else
         model_errors = project.errors.full_messages.to_sentence
@@ -67,5 +69,13 @@ module Projects
       log_error("Could not create wiki for #{project.full_name}")
       Gitlab::Metrics.counter(:wiki_can_not_be_created_total, 'Counts the times we failed to create a wiki')
     end
+
+    def update_pages_config
+      Projects::UpdatePagesConfigurationService.new(project).execute
+    end
+
+    def changing_pages_https_only?
+      project.previous_changes.include?(:pages_https_only)
+    end
   end
 end
diff --git a/app/validators/certificate_validator.rb b/app/validators/certificate_validator.rb
index 5239e70a326..b0c9a1b92a4 100644
--- a/app/validators/certificate_validator.rb
+++ b/app/validators/certificate_validator.rb
@@ -16,8 +16,6 @@ class CertificateValidator < ActiveModel::EachValidator
   private
 
   def valid_certificate_pem?(value)
-    return false unless value
-
     OpenSSL::X509::Certificate.new(value).present?
   rescue OpenSSL::X509::CertificateError
     false
diff --git a/app/views/projects/pages/_https_only.html.haml b/app/views/projects/pages/_https_only.html.haml
new file mode 100644
index 00000000000..6a3ffce949f
--- /dev/null
+++ b/app/views/projects/pages/_https_only.html.haml
@@ -0,0 +1,10 @@
+= form_for @project, url: namespace_project_pages_path(@project.namespace.becomes(Namespace), @project), html: { class: 'inline', title: pages_https_only_title } do |f|
+  = f.check_box :pages_https_only, class: 'pull-left', disabled: pages_https_only_disabled?
+
+  .prepend-left-20
+    = f.label :pages_https_only, class: pages_https_only_label_class do
+      %strong Force domains with SSL certificates to use HTTPS
+
+  - unless pages_https_only_disabled?
+    .prepend-top-10
+    = f.submit 'Save', class: 'btn btn-success'
diff --git a/app/views/projects/pages/show.html.haml b/app/views/projects/pages/show.html.haml
index 04e647c0dc6..f17d9d24db6 100644
--- a/app/views/projects/pages/show.html.haml
+++ b/app/views/projects/pages/show.html.haml
@@ -13,6 +13,9 @@
   Combined with the power of GitLab CI and the help of GitLab Runner
   you can deploy static pages for your individual projects, your user or your group.
 
+- if Gitlab.config.pages.external_https
+  = render 'https_only'
+
 %hr.clearfix
 
 = render 'access'
diff --git a/changelogs/unreleased/pages_force_https.yml b/changelogs/unreleased/pages_force_https.yml
new file mode 100644
index 00000000000..da7e29087f3
--- /dev/null
+++ b/changelogs/unreleased/pages_force_https.yml
@@ -0,0 +1,5 @@
+---
+title: Add HTTPS-only pages
+merge_request: 16273
+author: rfwatson
+type: added
diff --git a/config/routes/project.rb b/config/routes/project.rb
index c803737d40b..f50b9aded8d 100644
--- a/config/routes/project.rb
+++ b/config/routes/project.rb
@@ -52,7 +52,7 @@ constraints(::Constraints::ProjectUrlConstrainer.new) do
         end
       end
 
-      resource :pages, only: [:show, :destroy] do
+      resource :pages, only: [:show, :update, :destroy] do
         resources :domains, except: :index, controller: 'pages_domains', constraints: { id: %r{[^/]+} } do
           member do
             post :verify
diff --git a/db/migrate/20180102220145_add_pages_https_only_to_projects.rb b/db/migrate/20180102220145_add_pages_https_only_to_projects.rb
new file mode 100644
index 00000000000..ef6bc6896c0
--- /dev/null
+++ b/db/migrate/20180102220145_add_pages_https_only_to_projects.rb
@@ -0,0 +1,9 @@
+class AddPagesHttpsOnlyToProjects < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def change
+    add_column :projects, :pages_https_only, :boolean
+  end
+end
diff --git a/db/migrate/20180109183319_change_default_value_for_pages_https_only.rb b/db/migrate/20180109183319_change_default_value_for_pages_https_only.rb
new file mode 100644
index 00000000000..c242e1b0d24
--- /dev/null
+++ b/db/migrate/20180109183319_change_default_value_for_pages_https_only.rb
@@ -0,0 +1,13 @@
+class ChangeDefaultValueForPagesHttpsOnly < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def up
+    change_column_default :projects, :pages_https_only, true
+  end
+
+  def down
+    change_column_default :projects, :pages_https_only, nil
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 56116a2d241..1be0570f85a 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -1513,6 +1513,7 @@ ActiveRecord::Schema.define(version: 20180320182229) do
     t.boolean "merge_requests_ff_only_enabled", default: false
     t.boolean "merge_requests_rebase_enabled", default: false, null: false
     t.integer "jobs_cache_index"
+    t.boolean "pages_https_only", default: true
   end
 
   add_index "projects", ["ci_id"], name: "index_projects_on_ci_id", using: :btree
diff --git a/spec/controllers/projects/pages_controller_spec.rb b/spec/controllers/projects/pages_controller_spec.rb
index 4705c50de7e..11f54eef531 100644
--- a/spec/controllers/projects/pages_controller_spec.rb
+++ b/spec/controllers/projects/pages_controller_spec.rb
@@ -65,4 +65,41 @@ describe Projects::PagesController do
       end
     end
   end
+
+  describe 'PATCH update' do
+    let(:request_params) do
+      {
+        namespace_id: project.namespace,
+        project_id: project,
+        project: { pages_https_only: false }
+      }
+    end
+
+    let(:update_service) { double(execute: { status: :success }) }
+
+    before do
+      allow(Projects::UpdateService).to receive(:new) { update_service }
+    end
+
+    it 'returns 302 status' do
+      patch :update, request_params
+
+      expect(response).to have_gitlab_http_status(:found)
+    end
+
+    it 'redirects back to the pages settings' do
+      patch :update, request_params
+
+      expect(response).to redirect_to(project_pages_path(project))
+    end
+
+    it 'calls the update service' do
+      expect(Projects::UpdateService)
+        .to receive(:new)
+        .with(project, user, request_params[:project])
+        .and_return(update_service)
+
+      patch :update, request_params
+    end
+  end
 end
diff --git a/spec/controllers/projects/pages_domains_controller_spec.rb b/spec/controllers/projects/pages_domains_controller_spec.rb
index 83a3799e883..d4058a5c515 100644
--- a/spec/controllers/projects/pages_domains_controller_spec.rb
+++ b/spec/controllers/projects/pages_domains_controller_spec.rb
@@ -13,7 +13,7 @@ describe Projects::PagesDomainsController do
   end
 
   let(:pages_domain_params) do
-    build(:pages_domain, :with_certificate, :with_key, domain: 'my.otherdomain.com').slice(:key, :certificate, :domain)
+    build(:pages_domain, domain: 'my.otherdomain.com').slice(:key, :certificate, :domain)
   end
 
   before do
@@ -68,7 +68,7 @@ describe Projects::PagesDomainsController do
     end
 
     let(:pages_domain_params) do
-      attributes_for(:pages_domain, :with_certificate, :with_key).slice(:key, :certificate)
+      attributes_for(:pages_domain).slice(:key, :certificate)
     end
 
     let(:params) do
diff --git a/spec/factories/pages_domains.rb b/spec/factories/pages_domains.rb
index 35b44e1c52e..20671da016e 100644
--- a/spec/factories/pages_domains.rb
+++ b/spec/factories/pages_domains.rb
@@ -4,6 +4,38 @@ FactoryBot.define do
     verified_at { Time.now }
     enabled_until { 1.week.from_now }
 
+    certificate '-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----'
+
+    key '-----BEGIN PRIVATE KEY-----
+MIICdgIBADANBgkqhkiG9w0BAQEFAASCAmAwggJcAgEAAoGBAKS+CfS9GcRSdYSN
+SzyH5QJQBr5umRL6E+KilOV39iYFO/9oHjUdapTRWkrwnNPCp7qaeck4Jr8iv14t
+PVNDfNr76eGb6/3YknOAP0QOjLWunoC8kjU+N/JHU52NrUeX3qEy8EKV9LeCDJcB
+kBk+Yejn9nypg8c7sLsn33CB6i3bAgMBAAECgYA2D26w80T7WZvazYr86BNMePpd
+j2mIAqx32KZHzt/lhh40J/SRtX9+Kl0Y7nBoRR5Ja9u/HkAIxNxLiUjwg9r6cpg/
+uITEF5nMt7lAk391BuI+7VOZZGbJDsq2ulPd6lO+C8Kq/PI/e4kXcIjeH6KwQsuR
+5vrXfBZ3sQfflaiN4QJBANBt8JY2LIGQF8o89qwUpRL5vbnKQ4IzZ5+TOl4RLR7O
+AQpJ81tGuINghO7aunctb6rrcKJrxmEH1whzComybrMCQQDKV49nOBudRBAIgG4K
+EnLzsRKISUHMZSJiYTYnablof8cKw1JaQduw7zgrUlLwnroSaAGX88+Jw1f5n2Lh
+Vlg5AkBDdUGnrDLtYBCDEQYZHblrkc7ZAeCllDOWjxUV+uMqlCv8A4Ey6omvY57C
+m6I8DkWVAQx8VPtozhvHjUw80rZHAkB55HWHAM3h13axKG0htCt7klhPsZHpx6MH
+EPjGlXIT+aW2XiPmK3ZlCDcWIenE+lmtbOpI159Wpk8BGXs/s/xBAkEAlAY3ymgx
+63BDJEwvOb2IaP8lDDxNsXx9XJNVvQbv5n15vNsLHbjslHfAhAbxnLQ1fLhUPqSi
+nNp/xedE1YxutQ==
+-----END PRIVATE KEY-----'
+
     trait :disabled do
       verified_at nil
       enabled_until nil
@@ -21,40 +53,12 @@ FactoryBot.define do
       enabled_until { 1.hour.ago }
     end
 
-    trait :with_certificate do
-      certificate '-----BEGIN CERTIFICATE-----
-MIICGzCCAYSgAwIBAgIBATANBgkqhkiG9w0BAQUFADAbMRkwFwYDVQQDExB0ZXN0
-LWNlcnRpZmljYXRlMB4XDTE2MDIxMjE0MzIwMFoXDTIwMDQxMjE0MzIwMFowGzEZ
-MBcGA1UEAxMQdGVzdC1jZXJ0aWZpY2F0ZTCBnzANBgkqhkiG9w0BAQEFAAOBjQAw
-gYkCgYEApL4J9L0ZxFJ1hI1LPIflAlAGvm6ZEvoT4qKU5Xf2JgU7/2geNR1qlNFa
-SvCc08Knupp5yTgmvyK/Xi09U0N82vvp4Zvr/diSc4A/RA6Mta6egLySNT438kdT
-nY2tR5feoTLwQpX0t4IMlwGQGT5h6Of2fKmDxzuwuyffcIHqLdsCAwEAAaNvMG0w
-DAYDVR0TAQH/BAIwADAdBgNVHQ4EFgQUxl9WSxBprB0z0ibJs3rXEk0+95AwCwYD
-VR0PBAQDAgXgMBEGCWCGSAGG+EIBAQQEAwIGQDAeBglghkgBhvhCAQ0EERYPeGNh
-IGNlcnRpZmljYXRlMA0GCSqGSIb3DQEBBQUAA4GBAGC4T8SlFHK0yPSa+idGLQFQ
-joZp2JHYvNlTPkRJ/J4TcXxBTJmArcQgTIuNoBtC+0A/SwdK4MfTCUY4vNWNdese
-5A4K65Nb7Oh1AdQieTBHNXXCdyFsva9/ScfQGEl7p55a52jOPs0StPd7g64uvjlg
-YHi2yesCrOvVXt+lgPTd
------END CERTIFICATE-----'
+    trait :without_certificate do
+      certificate nil
     end
 
-    trait :with_key do
-      key '-----BEGIN PRIVATE KEY-----
-MIICdgIBADANBgkqhkiG9w0BAQEFAASCAmAwggJcAgEAAoGBAKS+CfS9GcRSdYSN
-SzyH5QJQBr5umRL6E+KilOV39iYFO/9oHjUdapTRWkrwnNPCp7qaeck4Jr8iv14t
-PVNDfNr76eGb6/3YknOAP0QOjLWunoC8kjU+N/JHU52NrUeX3qEy8EKV9LeCDJcB
-kBk+Yejn9nypg8c7sLsn33CB6i3bAgMBAAECgYA2D26w80T7WZvazYr86BNMePpd
-j2mIAqx32KZHzt/lhh40J/SRtX9+Kl0Y7nBoRR5Ja9u/HkAIxNxLiUjwg9r6cpg/
-uITEF5nMt7lAk391BuI+7VOZZGbJDsq2ulPd6lO+C8Kq/PI/e4kXcIjeH6KwQsuR
-5vrXfBZ3sQfflaiN4QJBANBt8JY2LIGQF8o89qwUpRL5vbnKQ4IzZ5+TOl4RLR7O
-AQpJ81tGuINghO7aunctb6rrcKJrxmEH1whzComybrMCQQDKV49nOBudRBAIgG4K
-EnLzsRKISUHMZSJiYTYnablof8cKw1JaQduw7zgrUlLwnroSaAGX88+Jw1f5n2Lh
-Vlg5AkBDdUGnrDLtYBCDEQYZHblrkc7ZAeCllDOWjxUV+uMqlCv8A4Ey6omvY57C
-m6I8DkWVAQx8VPtozhvHjUw80rZHAkB55HWHAM3h13axKG0htCt7klhPsZHpx6MH
-EPjGlXIT+aW2XiPmK3ZlCDcWIenE+lmtbOpI159Wpk8BGXs/s/xBAkEAlAY3ymgx
-63BDJEwvOb2IaP8lDDxNsXx9XJNVvQbv5n15vNsLHbjslHfAhAbxnLQ1fLhUPqSi
-nNp/xedE1YxutQ==
------END PRIVATE KEY-----'
+    trait :without_key do
+      key nil
     end
 
     trait :with_missing_chain do
diff --git a/spec/features/projects/pages_spec.rb b/spec/features/projects/pages_spec.rb
index 233d2e67b9d..020738ae865 100644
--- a/spec/features/projects/pages_spec.rb
+++ b/spec/features/projects/pages_spec.rb
@@ -40,11 +40,6 @@ feature 'Pages' do
       end
 
       context 'when support for external domains is disabled' do
-        before do
-          allow(Gitlab.config.pages).to receive(:external_http).and_return(nil)
-          allow(Gitlab.config.pages).to receive(:external_https).and_return(nil)
-        end
-
         it 'renders message that support is disabled' do
           visit project_pages_path(project)
 
@@ -52,7 +47,9 @@ feature 'Pages' do
         end
       end
 
-      context 'when pages are exposed on external HTTP address' do
+      context 'when pages are exposed on external HTTP address', :http_pages_enabled do
+        given(:project) { create(:project, pages_https_only: false) }
+
         shared_examples 'adds new domain' do
           it 'adds new domain' do
             visit new_project_pages_domain_path(project)
@@ -64,11 +61,6 @@ feature 'Pages' do
           end
         end
 
-        before do
-          allow(Gitlab.config.pages).to receive(:external_http).and_return(['1.1.1.1:80'])
-          allow(Gitlab.config.pages).to receive(:external_https).and_return(nil)
-        end
-
         it 'allows to add new domain' do
           visit project_pages_path(project)
 
@@ -80,13 +72,13 @@ feature 'Pages' do
         context 'when project in group namespace' do
           it_behaves_like 'adds new domain' do
             let(:group) { create :group }
-            let(:project) { create :project, namespace: group }
+            let(:project) { create(:project, namespace: group, pages_https_only: false) }
           end
         end
 
         context 'when pages domain is added' do
           before do
-            project.pages_domains.create!(domain: 'my.test.domain.com')
+            create(:pages_domain, project: project, domain: 'my.test.domain.com')
 
             visit new_project_pages_domain_path(project)
           end
@@ -104,7 +96,7 @@ feature 'Pages' do
         end
       end
 
-      context 'when pages are exposed on external HTTPS address' do
+      context 'when pages are exposed on external HTTPS address', :https_pages_enabled do
         let(:certificate_pem) do
           <<~PEM
           -----BEGIN CERTIFICATE-----
@@ -145,11 +137,6 @@ feature 'Pages' do
           KEY
         end
 
-        before do
-          allow(Gitlab.config.pages).to receive(:external_http).and_return(['1.1.1.1:80'])
-          allow(Gitlab.config.pages).to receive(:external_https).and_return(['1.1.1.1:443'])
-        end
-
         it 'adds new domain with certificate' do
           visit new_project_pages_domain_path(project)
 
@@ -163,7 +150,7 @@ feature 'Pages' do
 
         describe 'updating the certificate for an existing domain' do
           let!(:domain) do
-            create(:pages_domain, :with_key, :with_certificate, project: project)
+            create(:pages_domain, project: project)
           end
 
           it 'allows the certificate to be updated' do
@@ -237,6 +224,69 @@ feature 'Pages' do
     it_behaves_like 'no pages deployed'
   end
 
+  describe 'HTTPS settings', :js, :https_pages_enabled do
+    background do
+      project.namespace.update(owner: user)
+
+      allow_any_instance_of(Project).to receive(:pages_deployed?) { true }
+    end
+
+    scenario 'tries to change the setting' do
+      visit project_pages_path(project)
+      expect(page).to have_content("Force domains with SSL certificates to use HTTPS")
+
+      uncheck :project_pages_https_only
+
+      click_button 'Save'
+
+      expect(page).to have_text('Your changes have been saved')
+      expect(page).not_to have_checked_field('project_pages_https_only')
+    end
+
+    context 'setting could not be updated' do
+      before do
+        allow_any_instance_of(Projects::UpdateService)
+          .to receive(:execute)
+          .and_return(status: :error)
+      end
+
+      scenario 'tries to change the setting' do
+        visit project_pages_path(project)
+
+        uncheck :project_pages_https_only
+
+        click_button 'Save'
+
+        expect(page).to have_text('Something went wrong on our end')
+      end
+    end
+
+    context 'non-HTTPS domain exists' do
+      given(:project) { create(:project, pages_https_only: false) }
+
+      before do
+        create(:pages_domain, :without_key, :without_certificate, project: project)
+      end
+
+      scenario 'the setting is disabled' do
+        visit project_pages_path(project)
+
+        expect(page).to have_field(:project_pages_https_only, disabled: true)
+        expect(page).not_to have_button('Save')
+      end
+    end
+
+    context 'HTTPS pages are disabled', :https_pages_disabled do
+      scenario 'the setting is unavailable' do
+        visit project_pages_path(project)
+
+        expect(page).not_to have_field(:project_pages_https_only)
+        expect(page).not_to have_content('Force domains with SSL certificates to use HTTPS')
+        expect(page).not_to have_button('Save')
+      end
+    end
+  end
+
   describe 'Remove page' do
     context 'when user is the owner' do
       let(:project) { create :project, :repository }
diff --git a/spec/lib/gitlab/import_export/safe_model_attributes.yml b/spec/lib/gitlab/import_export/safe_model_attributes.yml
index 0b938892da5..44e4c6ff94b 100644
--- a/spec/lib/gitlab/import_export/safe_model_attributes.yml
+++ b/spec/lib/gitlab/import_export/safe_model_attributes.yml
@@ -458,6 +458,7 @@ Project:
 - merge_requests_ff_only_enabled
 - merge_requests_rebase_enabled
 - jobs_cache_index
+- pages_https_only
 Author:
 - name
 ProjectFeature:
diff --git a/spec/models/pages_domain_spec.rb b/spec/models/pages_domain_spec.rb
index 95713d8b85b..4b85c5e8720 100644
--- a/spec/models/pages_domain_spec.rb
+++ b/spec/models/pages_domain_spec.rb
@@ -18,24 +18,63 @@ describe PagesDomain do
       it { is_expected.to validate_uniqueness_of(:domain).case_insensitive }
     end
 
-    {
-      'my.domain.com'    => true,
-      '123.456.789'      => true,
-      '0x12345.com'      => true,
-      '0123123'          => true,
-      '_foo.com'         => false,
-      'reserved.com'     => false,
-      'a.reserved.com'   => false,
-      nil                => false
-    }.each do |value, validity|
-      context "domain #{value.inspect} validity" do
-        before do
-          allow(Settings.pages).to receive(:host).and_return('reserved.com')
+    describe "hostname" do
+      {
+        'my.domain.com'    => true,
+        '123.456.789'      => true,
+        '0x12345.com'      => true,
+        '0123123'          => true,
+        '_foo.com'         => false,
+        'reserved.com'     => false,
+        'a.reserved.com'   => false,
+        nil                => false
+      }.each do |value, validity|
+        context "domain #{value.inspect} validity" do
+          before do
+            allow(Settings.pages).to receive(:host).and_return('reserved.com')
+          end
+
+          let(:domain) { value }
+
+          it { expect(pages_domain.valid?).to eq(validity) }
         end
+      end
+    end
 
-        let(:domain) { value }
+    describe "HTTPS-only" do
+      using RSpec::Parameterized::TableSyntax
 
-        it { expect(pages_domain.valid?).to eq(validity) }
+      let(:domain) { 'my.domain.com' }
+
+      let(:project) do
+        instance_double(Project, pages_https_only?: pages_https_only)
+      end
+
+      let(:pages_domain) do
+        build(:pages_domain, certificate: certificate, key: key).tap do |pd|
+          allow(pd).to receive(:project).and_return(project)
+          pd.valid?
+        end
+      end
+
+      where(:pages_https_only, :certificate, :key, :errors_on) do
+        attributes = attributes_for(:pages_domain)
+        cert, key = attributes.fetch_values(:certificate, :key)
+
+        true  | nil  | nil | %i(certificate key)
+        true  | cert | nil | %i(key)
+        true  | nil  | key | %i(certificate key)
+        true  | cert | key | []
+        false | nil  | nil | []
+        false | cert | nil | %i(key)
+        false | nil  | key | %i(key)
+        false | cert | key | []
+      end
+
+      with_them do
+        it "is adds the expected errors" do
+          expect(pages_domain.errors.keys).to eq errors_on
+        end
       end
     end
   end
@@ -43,26 +82,26 @@ describe PagesDomain do
   describe 'validate certificate' do
     subject { domain }
 
-    context 'when only certificate is specified' do
-      let(:domain) { build(:pages_domain, :with_certificate) }
-
-      it { is_expected.not_to be_valid }
-    end
-
-    context 'when only key is specified' do
-      let(:domain) { build(:pages_domain, :with_key) }
-
-      it { is_expected.not_to be_valid }
-    end
-
     context 'with matching key' do
-      let(:domain) { build(:pages_domain, :with_certificate, :with_key) }
+      let(:domain) { build(:pages_domain) }
 
       it { is_expected.to be_valid }
     end
 
+    context 'when no certificate is specified' do
+      let(:domain) { build(:pages_domain, :without_certificate) }
+
+      it { is_expected.not_to be_valid }
+    end
+
+    context 'when no key is specified' do
+      let(:domain) { build(:pages_domain, :without_key) }
+
+      it { is_expected.not_to be_valid }
+    end
+
     context 'for not matching key' do
-      let(:domain) { build(:pages_domain, :with_missing_chain, :with_key) }
+      let(:domain) { build(:pages_domain, :with_missing_chain) }
 
       it { is_expected.not_to be_valid }
     end
@@ -103,30 +142,26 @@ describe PagesDomain do
   describe '#url' do
     subject { domain.url }
 
+    let(:domain) { build(:pages_domain) }
+
+    it { is_expected.to eq("https://#{domain.domain}") }
+
     context 'without the certificate' do
-      let(:domain) { build(:pages_domain, certificate: '') }
+      let(:domain) { build(:pages_domain, :without_certificate) }
 
       it { is_expected.to eq("http://#{domain.domain}") }
     end
-
-    context 'with a certificate' do
-      let(:domain) { build(:pages_domain, :with_certificate) }
-
-      it { is_expected.to eq("https://#{domain.domain}") }
-    end
   end
 
   describe '#has_matching_key?' do
     subject { domain.has_matching_key? }
 
-    context 'for matching key' do
-      let(:domain) { build(:pages_domain, :with_certificate, :with_key) }
+    let(:domain) { build(:pages_domain) }
 
-      it { is_expected.to be_truthy }
-    end
+    it { is_expected.to be_truthy }
 
     context 'for invalid key' do
-      let(:domain) { build(:pages_domain, :with_missing_chain, :with_key) }
+      let(:domain) { build(:pages_domain, :with_missing_chain) }
 
       it { is_expected.to be_falsey }
     end
@@ -136,7 +171,7 @@ describe PagesDomain do
     subject { domain.has_intermediates? }
 
     context 'for self signed' do
-      let(:domain) { build(:pages_domain, :with_certificate) }
+      let(:domain) { build(:pages_domain) }
 
       it { is_expected.to be_truthy }
     end
@@ -162,7 +197,7 @@ describe PagesDomain do
     subject { domain.expired? }
 
     context 'for valid' do
-      let(:domain) { build(:pages_domain, :with_certificate) }
+      let(:domain) { build(:pages_domain) }
 
       it { is_expected.to be_falsey }
     end
@@ -175,7 +210,7 @@ describe PagesDomain do
   end
 
   describe '#subject' do
-    let(:domain) { build(:pages_domain, :with_certificate) }
+    let(:domain) { build(:pages_domain) }
 
     subject { domain.subject }
 
@@ -183,7 +218,7 @@ describe PagesDomain do
   end
 
   describe '#certificate_text' do
-    let(:domain) { build(:pages_domain, :with_certificate) }
+    let(:domain) { build(:pages_domain) }
 
     subject { domain.certificate_text }
 
@@ -191,6 +226,18 @@ describe PagesDomain do
     it { is_expected.not_to be_empty }
   end
 
+  describe "#https?" do
+    context "when a certificate is present" do
+      subject { build(:pages_domain) }
+      it { is_expected.to be_https }
+    end
+
+    context "when no certificate is present" do
+      subject { build(:pages_domain, :without_certificate) }
+      it { is_expected.not_to be_https }
+    end
+  end
+
   describe '#update_daemon' do
     it 'runs when the domain is created' do
       domain = build(:pages_domain)
@@ -267,29 +314,30 @@ describe PagesDomain do
       end
 
       context 'TLS configuration' do
-        set(:domain_with_tls) { create(:pages_domain, :with_key, :with_certificate) }
+        set(:domain_without_tls) { create(:pages_domain, :without_certificate, :without_key) }
+        set(:domain) { create(:pages_domain) }
 
-        let(:cert1) { domain_with_tls.certificate }
+        let(:cert1) { domain.certificate }
         let(:cert2) { cert1 + ' ' }
-        let(:key1) { domain_with_tls.key }
+        let(:key1) { domain.key }
         let(:key2) { key1 + ' ' }
 
         it 'updates when added' do
-          expect(domain).to receive(:update_daemon)
+          expect(domain_without_tls).to receive(:update_daemon)
 
-          domain.update!(key: key1, certificate: cert1)
+          domain_without_tls.update!(key: key1, certificate: cert1)
         end
 
         it 'updates when changed' do
-          expect(domain_with_tls).to receive(:update_daemon)
+          expect(domain).to receive(:update_daemon)
 
-          domain_with_tls.update!(key: key2, certificate: cert2)
+          domain.update!(key: key2, certificate: cert2)
         end
 
         it 'updates when removed' do
-          expect(domain_with_tls).to receive(:update_daemon)
+          expect(domain).to receive(:update_daemon)
 
-          domain_with_tls.update!(key: nil, certificate: nil)
+          domain.update!(key: nil, certificate: nil)
         end
       end
     end
diff --git a/spec/models/project_spec.rb b/spec/models/project_spec.rb
index 4cf8d861595..c522ab7c447 100644
--- a/spec/models/project_spec.rb
+++ b/spec/models/project_spec.rb
@@ -3479,4 +3479,49 @@ describe Project do
       end
     end
   end
+
+  describe "#pages_https_only?" do
+    subject { build(:project) }
+
+    context "when HTTPS pages are disabled" do
+      it { is_expected.not_to be_pages_https_only }
+    end
+
+    context "when HTTPS pages are enabled", :https_pages_enabled do
+      it { is_expected.to be_pages_https_only }
+    end
+  end
+
+  describe "#pages_https_only? validation", :https_pages_enabled do
+    subject(:project) do
+      # set-up dirty object:
+      create(:project, pages_https_only: false).tap do |p|
+        p.pages_https_only = true
+      end
+    end
+
+    context "when no domains are associated" do
+      it { is_expected.to be_valid }
+    end
+
+    context "when domains including keys and certificates are associated" do
+      before do
+        allow(project)
+          .to receive(:pages_domains)
+          .and_return([instance_double(PagesDomain, https?: true)])
+      end
+
+      it { is_expected.to be_valid }
+    end
+
+    context "when domains including no keys or certificates are associated" do
+      before do
+        allow(project)
+          .to receive(:pages_domains)
+          .and_return([instance_double(PagesDomain, https?: false)])
+      end
+
+      it { is_expected.not_to be_valid }
+    end
+  end
 end
diff --git a/spec/requests/api/pages_domains_spec.rb b/spec/requests/api/pages_domains_spec.rb
index dc3a116c060..a9ccbb32666 100644
--- a/spec/requests/api/pages_domains_spec.rb
+++ b/spec/requests/api/pages_domains_spec.rb
@@ -1,17 +1,17 @@
 require 'rails_helper'
 
 describe API::PagesDomains do
-  set(:project) { create(:project, path: 'my.project') }
+  set(:project) { create(:project, path: 'my.project', pages_https_only: false) }
   set(:user) { create(:user) }
   set(:admin) { create(:admin) }
 
-  set(:pages_domain) { create(:pages_domain, domain: 'www.domain.test', project: project) }
-  set(:pages_domain_secure) { create(:pages_domain, :with_certificate, :with_key, domain: 'ssl.domain.test', project: project) }
-  set(:pages_domain_expired) { create(:pages_domain, :with_expired_certificate, :with_key, domain: 'expired.domain.test', project: project) }
+  set(:pages_domain) { create(:pages_domain, :without_key, :without_certificate, domain: 'www.domain.test', project: project) }
+  set(:pages_domain_secure) { create(:pages_domain, domain: 'ssl.domain.test', project: project) }
+  set(:pages_domain_expired) { create(:pages_domain, :with_expired_certificate, domain: 'expired.domain.test', project: project) }
 
-  let(:pages_domain_params) { build(:pages_domain, domain: 'www.other-domain.test').slice(:domain) }
-  let(:pages_domain_secure_params) { build(:pages_domain, :with_certificate, :with_key, domain: 'ssl.other-domain.test', project: project).slice(:domain, :certificate, :key) }
-  let(:pages_domain_secure_key_missmatch_params) {build(:pages_domain, :with_trusted_chain, :with_key, project: project).slice(:domain, :certificate, :key) }
+  let(:pages_domain_params) { build(:pages_domain, :without_key, :without_certificate, domain: 'www.other-domain.test').slice(:domain) }
+  let(:pages_domain_secure_params) { build(:pages_domain, domain: 'ssl.other-domain.test', project: project).slice(:domain, :certificate, :key) }
+  let(:pages_domain_secure_key_missmatch_params) {build(:pages_domain, :with_trusted_chain, project: project).slice(:domain, :certificate, :key) }
   let(:pages_domain_secure_missing_chain_params) {build(:pages_domain, :with_missing_chain, project: project).slice(:certificate) }
 
   let(:route) { "/projects/#{project.id}/pages/domains" }
diff --git a/spec/services/projects/update_service_spec.rb b/spec/services/projects/update_service_spec.rb
index f3f97b6b921..497c1949256 100644
--- a/spec/services/projects/update_service_spec.rb
+++ b/spec/services/projects/update_service_spec.rb
@@ -241,6 +241,27 @@ describe Projects::UpdateService do
         })
       end
     end
+
+    context 'when updating #pages_https_only', :https_pages_enabled do
+      subject(:call_service) do
+        update_project(project, admin, pages_https_only: false)
+      end
+
+      it 'updates the attribute' do
+        expect { call_service }
+          .to change { project.pages_https_only? }
+          .to(false)
+      end
+
+      it 'calls Projects::UpdatePagesConfigurationService' do
+        expect(Projects::UpdatePagesConfigurationService)
+          .to receive(:new)
+          .with(project)
+          .and_call_original
+
+        call_service
+      end
+    end
   end
 
   describe '#run_auto_devops_pipeline?' do
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 9f6f0204a16..5051cd34564 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -197,6 +197,22 @@ RSpec.configure do |config|
       Ability.allowed?(*args)
     end
   end
+
+  config.before(:each, :http_pages_enabled) do |_|
+    allow(Gitlab.config.pages).to receive(:external_http).and_return(['1.1.1.1:80'])
+  end
+
+  config.before(:each, :https_pages_enabled) do |_|
+    allow(Gitlab.config.pages).to receive(:external_https).and_return(['1.1.1.1:443'])
+  end
+
+  config.before(:each, :http_pages_disabled) do |_|
+    allow(Gitlab.config.pages).to receive(:external_http).and_return(false)
+  end
+
+  config.before(:each, :https_pages_disabled) do |_|
+    allow(Gitlab.config.pages).to receive(:external_https).and_return(false)
+  end
 end
 
 # add simpler way to match asset paths containing digest strings