diff --git a/doc/api/repositories.md b/doc/api/repositories.md
index 7a9f766ba1d..229d4409ea6 100644
--- a/doc/api/repositories.md
+++ b/doc/api/repositories.md
@@ -239,6 +239,34 @@ Parameters:
 ]
 ```
 
+## Get the diff of a commit
+
+Get the diff of a commit in a project.
+
+```
+GET /projects/:id/repository/commit/:sha
+```
+
+Parameters:
+
++ `id` (required) - The ID of a project
++ `sha` (required) - The name of a repository branch or tag or if not given the default branch
+
+```json
+[
+  {
+    "diff": "--- a/doc/update/5.4-to-6.0.md\n+++ b/doc/update/5.4-to-6.0.md\n@@ -71,6 +71,8 @@\n sudo -u git -H bundle exec rake migrate_keys RAILS_ENV=production\n sudo -u git -H bundle exec rake migrate_inline_notes RAILS_ENV=production\n \n+sudo -u git -H bundle exec rake assets:precompile RAILS_ENV=production\n+\n ```\n \n ### 6. Update config files",
+    "new_path": "doc/update/5.4-to-6.0.md",
+    "old_path": "doc/update/5.4-to-6.0.md",
+    "a_mode": null,
+    "b_mode": "100644",
+    "new_file": false,
+    "renamed_file": false,
+    "deleted_file": false
+  }
+]
+```
+
 ## List repository tree
 
 Get a list of repository files and directories in a project.
diff --git a/lib/api/repositories.rb b/lib/api/repositories.rb
index 5db17b7e414..7e806546d02 100644
--- a/lib/api/repositories.rb
+++ b/lib/api/repositories.rb
@@ -102,6 +102,20 @@ module API
         present commits, with: Entities::RepoCommit
       end
 
+      # Get a specific commit of a project
+      #
+      # Parameters:
+      #   id (required) - The ID of a project
+      #   sha (required) - The commit or branch name
+      # Example Request:
+      #   GET /projects/:id/repository/commit/:sha
+      get ":id/repository/commit/:sha" do
+        authorize! :download_code, user_project
+        sha = params[:sha]
+        result = CommitLoadContext.new(user_project, current_user, {id: sha}).execute
+        result[:commit].diffs
+      end
+
       # Get a project repository tree
       #
       # Parameters:
diff --git a/spec/requests/api/repositories_spec.rb b/spec/requests/api/repositories_spec.rb
index afa67d1ecbe..44892876ccb 100644
--- a/spec/requests/api/repositories_spec.rb
+++ b/spec/requests/api/repositories_spec.rb
@@ -112,6 +112,28 @@ describe API::API do
     end
   end
 
+  describe "GET /projects:id/repository/commit/:sha" do
+    context "authorized user" do
+      before { project.team << [user2, :reporter] }
+
+      it "should return the diff of the selected commit" do
+        get api("/projects/#{project.id}/repository/commit/#{project.repository.commit.id}", user)
+        response.status.should == 200
+
+        json_response.should be_an Array
+        json_response.length.should >= 1
+        json_response.first.keys.should include "diff"
+      end
+    end
+
+    context "unauthorized user" do
+      it "should not return the diff of the selected commit" do
+        get api("/projects/#{project.id}/repository/commit/#{project.repository.commit.id}")
+        response.status.should == 401
+      end
+    end
+  end
+
   describe "GET /projects/:id/repository/tree" do
     context "authorized user" do
       before { project.team << [user2, :reporter] }