diff --git a/lib/auth/github_authenticator.rb b/lib/auth/github_authenticator.rb
index 96fe5bfa7aa..c76fe9a59e2 100644
--- a/lib/auth/github_authenticator.rb
+++ b/lib/auth/github_authenticator.rb
@@ -78,6 +78,12 @@ class Auth::GithubAuthenticator < Auth::Authenticator
       user = user_info.user
       result.email = data[:email]
       result.email_valid = data[:email].present?
+
+      # update GitHub screen_name
+      if user_info.screen_name != screen_name
+        user_info.screen_name = screen_name
+        user_info.save!
+      end
     else
       # Potentially use *any* of the emails from GitHub to find a match or
       # register a new user, with preference given to the primary email.
diff --git a/spec/components/auth/github_authenticator_spec.rb b/spec/components/auth/github_authenticator_spec.rb
index 37c14b15464..ae50424c904 100644
--- a/spec/components/auth/github_authenticator_spec.rb
+++ b/spec/components/auth/github_authenticator_spec.rb
@@ -60,6 +60,17 @@ describe Auth::GithubAuthenticator do
       expect(result.email_valid).to eq(true)
     end
 
+    it 'can authenticate and update GitHub screen_name for existing user' do
+      GithubUserInfo.create!(user_id: user.id, github_user_id: 100, screen_name: "boris")
+
+      result = authenticator.after_authenticate(data)
+
+      expect(result.user.id).to eq(user.id)
+      expect(result.email).to eq(user.email)
+      expect(result.email_valid).to eq(true)
+      expect(GithubUserInfo.where(user_id: user.id).pluck(:screen_name)).to eq([user.username])
+    end
+
     it 'should use primary email for new user creation over other available emails' do
       hash = {
         extra: {