diff --git a/app/views/projects/variables/_form.html.haml b/app/views/projects/variables/_form.html.haml
index a5bae83e0ce..1ae86d258af 100644
--- a/app/views/projects/variables/_form.html.haml
+++ b/app/views/projects/variables/_form.html.haml
@@ -6,5 +6,5 @@
     = f.text_field :key, class: "form-control", placeholder: "PROJECT_VARIABLE", required: true
   .form-group
     = f.label :value, "Value", class: "label-light"
-    = f.text_area :value, class: "form-control", placeholder: "PROJECT_VARIABLE", required: true
+    = f.text_area :value, class: "form-control", placeholder: "PROJECT_VARIABLE"
   = f.submit btn_text, class: "btn btn-save"
diff --git a/changelogs/unreleased/lnovy-gitlab-ce-empty-variables.yml b/changelogs/unreleased/lnovy-gitlab-ce-empty-variables.yml
new file mode 100644
index 00000000000..bd5db5ac7af
--- /dev/null
+++ b/changelogs/unreleased/lnovy-gitlab-ce-empty-variables.yml
@@ -0,0 +1,4 @@
+---
+title: 'UI: Allow a project variable to be set to an empty value'
+merge_request: 6044
+author: Lukáš Nový
diff --git a/spec/features/variables_spec.rb b/spec/features/variables_spec.rb
index 9a4bc027004..a362d6fd3b6 100644
--- a/spec/features/variables_spec.rb
+++ b/spec/features/variables_spec.rb
@@ -3,7 +3,7 @@ require 'spec_helper'
 describe 'Project variables', js: true do
   let(:user)     { create(:user) }
   let(:project)  { create(:project) }
-  let(:variable) { create(:ci_variable, key: 'test') }
+  let(:variable) { create(:ci_variable, key: 'test_key', value: 'test value') }
 
   before do
     login_as(user)
@@ -24,11 +24,23 @@ describe 'Project variables', js: true do
     fill_in('variable_value', with: 'key value')
     click_button('Add new variable')
 
+    expect(page).to have_content('Variables were successfully updated.')
     page.within('.variables-table') do
       expect(page).to have_content('key')
     end
   end
 
+  it 'adds empty variable' do
+    fill_in('variable_key', with: 'new_key')
+    fill_in('variable_value', with: '')
+    click_button('Add new variable')
+
+    expect(page).to have_content('Variables were successfully updated.')
+    page.within('.variables-table') do
+      expect(page).to have_content('new_key')
+    end
+  end
+
   it 'reveals and hides new variable' do
     fill_in('variable_key', with: 'key')
     fill_in('variable_value', with: 'key value')
@@ -72,8 +84,20 @@ describe 'Project variables', js: true do
     fill_in('variable_value', with: 'key value')
     click_button('Save variable')
 
+    expect(page).to have_content('Variable was successfully updated.')
+    expect(project.variables.first.value).to eq('key value')
+  end
+
+  it 'edits variable with empty value' do
     page.within('.variables-table') do
-      expect(page).to have_content('key')
+      find('.btn-variable-edit').click
     end
+
+    expect(page).to have_content('Update variable')
+    fill_in('variable_value', with: '')
+    click_button('Save variable')
+
+    expect(page).to have_content('Variable was successfully updated.')
+    expect(project.variables.first.value).to eq('')
   end
 end