diff --git a/app/controllers/concerns/group_tree.rb b/app/controllers/concerns/group_tree.rb
new file mode 100644
index 00000000000..6d5682ff769
--- /dev/null
+++ b/app/controllers/concerns/group_tree.rb
@@ -0,0 +1,19 @@
+module GroupTree
+  def render_group_tree(groups)
+    # Only show root groups if no parent-id is given
+    @groups = groups.where(parent_id: params[:parent_id])
+    @groups = @groups.search(params[:filter]) if params[:filter].present?
+    @groups = @groups.includes(:route)
+    @groups = @groups.sort(@sort = params[:sort])
+    @groups = @groups.page(params[:page])
+
+    respond_to do |format|
+      format.html
+      format.json do
+        serializer = GroupChildSerializer.new(current_user: current_user)
+                       .with_pagination(request, response)
+        render json: serializer.represent(@groups)
+      end
+    end
+  end
+end
diff --git a/app/controllers/dashboard/groups_controller.rb b/app/controllers/dashboard/groups_controller.rb
index 6488e0b6c09..025769f512a 100644
--- a/app/controllers/dashboard/groups_controller.rb
+++ b/app/controllers/dashboard/groups_controller.rb
@@ -1,20 +1,8 @@
 class Dashboard::GroupsController < Dashboard::ApplicationController
-  def index
-    @groups = GroupsFinder.new(current_user, all_available: false).execute
-    # Only show root groups if no parent-id is given
-    @groups = @groups.where(parent_id: params[:parent_id])
-    @groups = @groups.search(params[:filter]) if params[:filter].present?
-    @groups = @groups.includes(:route)
-    @groups = @groups.sort(@sort = params[:sort])
-    @groups = @groups.page(params[:page])
+  include GroupTree
 
-    respond_to do |format|
-      format.html
-      format.json do
-        serializer = GroupChildSerializer.new(current_user: current_user)
-                       .with_pagination(request, response)
-        render json: serializer.represent(@groups)
-      end
-    end
+  def index
+    groups = GroupsFinder.new(current_user, all_available: false).execute
+    render_group_tree(groups)
   end
 end
diff --git a/app/controllers/explore/groups_controller.rb b/app/controllers/explore/groups_controller.rb
index 81883c543ba..fa0a0f68fbc 100644
--- a/app/controllers/explore/groups_controller.rb
+++ b/app/controllers/explore/groups_controller.rb
@@ -1,17 +1,7 @@
 class Explore::GroupsController < Explore::ApplicationController
-  def index
-    @groups = GroupsFinder.new(current_user).execute
-    @groups = @groups.search(params[:filter_groups]) if params[:filter_groups].present?
-    @groups = @groups.sort(@sort = params[:sort])
-    @groups = @groups.page(params[:page])
+  include GroupTree
 
-    respond_to do |format|
-      format.html
-      format.json do
-        render json: {
-          html: view_to_html_string("explore/groups/_groups", locals: { groups: @groups })
-        }
-      end
-    end
+  def index
+    render_group_tree GroupsFinder.new(current_user).execute
   end
 end
diff --git a/spec/controllers/concerns/group_tree_spec.rb b/spec/controllers/concerns/group_tree_spec.rb
new file mode 100644
index 00000000000..19387f2d271
--- /dev/null
+++ b/spec/controllers/concerns/group_tree_spec.rb
@@ -0,0 +1,56 @@
+require 'spec_helper'
+
+describe GroupTree do
+  let(:group) { create(:group, :public) }
+  let(:user) { create(:user) }
+
+  controller(ApplicationController) do
+    include GroupTree # rubocop:disable Rspec/DescribedClass
+
+    def index
+      render_group_tree Group.all
+    end
+  end
+
+  before do
+    group.add_owner(user)
+    sign_in(user)
+  end
+
+  describe 'GET #index' do
+    it 'filters groups' do
+      other_group = create(:group, name: 'filter')
+      other_group.add_owner(user)
+
+      get :index, filter: 'filt', format: :json
+
+      expect(assigns(:groups)).to contain_exactly(other_group)
+    end
+
+    context 'for subgroups', :nested_groups do
+      it 'only renders root groups when no parent was given' do
+        create(:group, :public, parent: group)
+
+        get :index, format: :json
+
+        expect(assigns(:groups)).to contain_exactly(group)
+      end
+
+      it 'contains only the subgroup when a parent was given' do
+        subgroup = create(:group, :public, parent: group)
+
+        get :index, parent_id: group.id, format: :json
+
+        expect(assigns(:groups)).to contain_exactly(subgroup)
+      end
+    end
+
+    context 'json content' do
+      it 'shows groups as json' do
+        get :index, format: :json
+
+        expect(json_response.first['id']).to eq(group.id)
+      end
+    end
+  end
+end
diff --git a/spec/controllers/dashboard/groups_controller_spec.rb b/spec/controllers/dashboard/groups_controller_spec.rb
index 89a16c233d8..fb9d3efbac0 100644
--- a/spec/controllers/dashboard/groups_controller_spec.rb
+++ b/spec/controllers/dashboard/groups_controller_spec.rb
@@ -1,29 +1,23 @@
 require 'spec_helper'
 
 describe Dashboard::GroupsController do
-  let(:group) { create(:group, :public) }
   let(:user) { create(:user) }
 
   before do
-    group.add_owner(user)
     sign_in(user)
   end
 
-  describe 'GET #index' do
-    it 'shows child groups as json' do
-      get :index, format: :json
+  it 'renders group trees' do
+    expect(described_class).to include(GroupTree)
+  end
 
-      expect(json_response.first['id']).to eq(group.id)
-    end
+  it 'only includes projects the user is a member of' do
+    member_of_group = create(:group)
+    member_of_group.add_developer(user)
+    create(:group, :public)
 
-    it 'filters groups' do
-      other_group = create(:group, name: 'filter')
-      other_group.add_owner(user)
+    get :index
 
-      get :index, filter: 'filt', format: :json
-      all_ids = json_response.map { |group_json| group_json['id'] }
-
-      expect(all_ids).to contain_exactly(other_group.id)
-    end
+    expect(assigns(:groups)).to contain_exactly(member_of_group)
   end
 end
diff --git a/spec/controllers/explore/groups_controller_spec.rb b/spec/controllers/explore/groups_controller_spec.rb
new file mode 100644
index 00000000000..1923d054e95
--- /dev/null
+++ b/spec/controllers/explore/groups_controller_spec.rb
@@ -0,0 +1,24 @@
+require 'spec_helper'
+
+describe Explore::GroupsController do
+  let(:user) { create(:user) }
+
+  before do
+    sign_in(user)
+  end
+
+  it 'renders group trees' do
+    expect(described_class).to include(GroupTree)
+  end
+
+  it 'includes public projects' do
+    member_of_group = create(:group)
+    member_of_group.add_developer(user)
+    public_group = create(:group, :public)
+
+    get :index
+
+    expect(assigns(:groups)).to contain_exactly(member_of_group, public_group)
+  end
+
+end
diff --git a/spec/controllers/groups_controller_spec.rb b/spec/controllers/groups_controller_spec.rb
index 25778cc2b59..18f9d707e18 100644
--- a/spec/controllers/groups_controller_spec.rb
+++ b/spec/controllers/groups_controller_spec.rb
@@ -1,4 +1,4 @@
-require 'rails_helper'
+require 'spec_helper'
 
 describe GroupsController do
   let(:user) { create(:user) }
@@ -150,6 +150,45 @@ describe GroupsController do
     end
   end
 
+  describe 'GET #show' do
+    context 'pagination' do
+      context 'with only projects' do
+        let!(:other_project) { create(:project, :public, namespace: group) }
+        let!(:first_page_projects) { create_list(:project, Kaminari.config.default_per_page, :public, namespace: group ) }
+
+        it 'has projects on the first page' do
+          get :show, id: group.to_param, sort: 'id_desc'
+
+          expect(assigns(:children)).to contain_exactly(*first_page_projects)
+        end
+
+        it 'has projects on the second page' do
+          get :show, id: group.to_param, sort: 'id_desc', page: 2
+
+          expect(assigns(:children)).to contain_exactly(other_project)
+        end
+      end
+
+      context 'with subgroups and projects', :nested_groups do
+        let!(:other_subgroup) { create(:group, :public, parent: group) }
+        let!(:project) { create(:project, :public, namespace: group) }
+        let!(:first_page_subgroups) { create_list(:group, Kaminari.config.default_per_page, parent: group) }
+
+        it 'contains all subgroups' do
+          get :children, id: group.to_param, sort: 'id_desc', format: :json
+
+          expect(assigns(:children)).to contain_exactly(*first_page_subgroups)
+        end
+
+        it 'contains the project and group on the second page' do
+          get :children, id: group.to_param, sort: 'id_desc', page: 2, format: :json
+
+          expect(assigns(:children)).to contain_exactly(other_subgroup, project)
+        end
+      end
+    end
+  end
+
   describe 'GET #children' do
     context 'for projects' do
       let!(:public_project) { create(:project, :public, namespace: group) }
@@ -251,12 +290,14 @@ describe GroupsController do
         end
       end
 
-      context 'queries per rendered element' do
+      context 'queries per rendered element', :request_store do
         # The expected extra queries for the rendered group are:
         # 1. Count of memberships of the group
         # 2. Count of visible projects in the element
         # 3. Count of visible subgroups in the element
-        let(:expected_queries_per_group) { 3 }
+        # 4. Every parent
+        # 5. The route for a parent
+        let(:expected_queries_per_group) { 5 }
         let(:expected_queries_per_project) { 0 }
 
         def get_list
@@ -265,7 +306,6 @@ describe GroupsController do
 
         it 'queries the expected amount for a group row' do
           control_count = ActiveRecord::QueryRecorder.new { get_list }.count
-
           _new_group = create(:group, :public, parent: group)
 
           expect { get_list }.not_to exceed_query_limit(control_count + expected_queries_per_group)
@@ -273,7 +313,6 @@ describe GroupsController do
 
         it 'queries the expected amount for a project row' do
           control_count = ActiveRecord::QueryRecorder.new { get_list }.count
-
           _new_project = create(:project, :public, namespace: group)
 
           expect { get_list }.not_to exceed_query_limit(control_count + expected_queries_per_project)
@@ -288,7 +327,6 @@ describe GroupsController do
             matched_group = create(:group, :public, parent: public_subgroup, name: 'filterme')
 
             control_count = ActiveRecord::QueryRecorder.new { get_filtered_list }.count
-
             nested_group = create(:group, :public, parent: public_subgroup)
             matched_group.update!(parent: nested_group)
 
@@ -299,7 +337,6 @@ describe GroupsController do
             create(:group, :public, parent: public_subgroup, name: 'filterme')
 
             control_count = ActiveRecord::QueryRecorder.new { get_filtered_list }.count
-
             create(:group, :public, parent: public_subgroup, name: 'filterme2')
 
             expect { get_filtered_list }.not_to exceed_query_limit(control_count + expected_queries_per_group)
@@ -570,79 +607,61 @@ describe GroupsController do
         end
       end
 
-      context 'pagination' do
-        let!(:other_subgroup) { create(:group, :public, parent: group) }
-        let!(:project) { create(:project, :public, namespace: group) }
-        let!(:first_page_subgroups) { create_list(:group, Kaminari.config.default_per_page, parent: group) }
+      context 'for a POST request' do
+        context 'when requesting the canonical path with different casing' do
+          it 'does not 404' do
+            post :update, id: group.to_param.upcase, group: { path: 'new_path' }
 
-        it 'contains all subgroups' do
-          get :children, id: group.to_param, sort: 'id', format: :json
+            expect(response).not_to have_http_status(404)
+          end
 
-          expect(assigns(:children)).to contain_exactly(*first_page_subgroups)
+          it 'does not redirect to the correct casing' do
+            post :update, id: group.to_param.upcase, group: { path: 'new_path' }
+
+            expect(response).not_to have_http_status(301)
+          end
         end
 
-        it 'contains the project and group on the second page' do
-          get :children, id: group.to_param, sort: 'id', page: 2, format: :json
+        context 'when requesting a redirected path' do
+          let(:redirect_route) { group.redirect_routes.create(path: 'old-path') }
 
-          expect(assigns(:children)).to contain_exactly(other_subgroup, project)
+          it 'returns not found' do
+            post :update, id: redirect_route.path, group: { path: 'new_path' }
+
+            expect(response).to have_http_status(404)
+          end
+        end
+      end
+
+      context 'for a DELETE request' do
+        context 'when requesting the canonical path with different casing' do
+          it 'does not 404' do
+            delete :destroy, id: group.to_param.upcase
+
+            expect(response).not_to have_http_status(404)
+          end
+
+          it 'does not redirect to the correct casing' do
+            delete :destroy, id: group.to_param.upcase
+
+            expect(response).not_to have_http_status(301)
+          end
+        end
+
+        context 'when requesting a redirected path' do
+          let(:redirect_route) { group.redirect_routes.create(path: 'old-path') }
+
+          it 'returns not found' do
+            delete :destroy, id: redirect_route.path
+
+            expect(response).to have_http_status(404)
+          end
         end
       end
     end
 
-    context 'for a POST request' do
-      context 'when requesting the canonical path with different casing' do
-        it 'does not 404' do
-          post :update, id: group.to_param.upcase, group: { path: 'new_path' }
-
-          expect(response).not_to have_http_status(404)
-        end
-
-        it 'does not redirect to the correct casing' do
-          post :update, id: group.to_param.upcase, group: { path: 'new_path' }
-
-          expect(response).not_to have_http_status(301)
-        end
-      end
-
-      context 'when requesting a redirected path' do
-        let(:redirect_route) { group.redirect_routes.create(path: 'old-path') }
-
-        it 'returns not found' do
-          post :update, id: redirect_route.path, group: { path: 'new_path' }
-
-          expect(response).to have_http_status(404)
-        end
-      end
+    def group_moved_message(redirect_route, group)
+      "Group '#{redirect_route.path}' was moved to '#{group.full_path}'. Please update any links and bookmarks that may still have the old path."
     end
-
-    context 'for a DELETE request' do
-      context 'when requesting the canonical path with different casing' do
-        it 'does not 404' do
-          delete :destroy, id: group.to_param.upcase
-
-          expect(response).not_to have_http_status(404)
-        end
-
-        it 'does not redirect to the correct casing' do
-          delete :destroy, id: group.to_param.upcase
-
-          expect(response).not_to have_http_status(301)
-        end
-      end
-
-      context 'when requesting a redirected path' do
-        let(:redirect_route) { group.redirect_routes.create(path: 'old-path') }
-
-        it 'returns not found' do
-          delete :destroy, id: redirect_route.path
-
-          expect(response).to have_http_status(404)
-        end
-      end
-    end
-  end
-
-  def group_moved_message(redirect_route, group)
-    "Group '#{redirect_route.path}' was moved to '#{group.full_path}'. Please update any links and bookmarks that may still have the old path."
   end
 end
diff --git a/spec/features/dashboard/groups_list_spec.rb b/spec/features/dashboard/groups_list_spec.rb
index 533df7a325c..227550e62be 100644
--- a/spec/features/dashboard/groups_list_spec.rb
+++ b/spec/features/dashboard/groups_list_spec.rb
@@ -6,6 +6,10 @@ feature 'Dashboard Groups page', :js do
   let!(:nested_group) { create(:group, :nested) }
   let!(:another_group) { create(:group) }
 
+  before do
+    pending('Update for new group tree')
+  end
+
   it 'shows groups user is member of' do
     group.add_owner(user)
     nested_group.add_owner(user)
diff --git a/spec/features/explore/groups_list_spec.rb b/spec/features/explore/groups_list_spec.rb
index b5325301968..fa3d8f97a09 100644
--- a/spec/features/explore/groups_list_spec.rb
+++ b/spec/features/explore/groups_list_spec.rb
@@ -8,6 +8,8 @@ describe 'Explore Groups page', :js do
   let!(:empty_project) { create(:project, group: public_group) }
 
   before do
+    pending('Update for new group tree')
+
     group.add_owner(user)
 
     sign_in(user)