diff --git a/app/models/project_services/chat_notification_service.rb b/app/models/project_services/chat_notification_service.rb
index ae0debbd3ace447eeda402aa8af09d61cce5cce8..a60b4c7fd0d5fa925b3e0c74abc740c12430e0f8 100644
--- a/app/models/project_services/chat_notification_service.rb
+++ b/app/models/project_services/chat_notification_service.rb
@@ -155,6 +155,7 @@ class ChatNotificationService < Service
   end
 
   def notify_for_ref?(data)
+    return true if data[:object_kind] == 'tag_push'
     return true if data.dig(:object_attributes, :tag)
     return true unless notify_only_default_branch?
 
diff --git a/changelogs/unreleased/45487-slack-tag-push-notifs.yml b/changelogs/unreleased/45487-slack-tag-push-notifs.yml
new file mode 100644
index 0000000000000000000000000000000000000000..647000bd97cc7376935f0ad22e0409c68b36afa5
--- /dev/null
+++ b/changelogs/unreleased/45487-slack-tag-push-notifs.yml
@@ -0,0 +1,5 @@
+---
+title: Fix chat service tag notifications not sending when only default branch enabled
+merge_request: 19864
+author:
+type: fixed
diff --git a/spec/support/shared_examples/slack_mattermost_notifications_shared_examples.rb b/spec/support/shared_examples/slack_mattermost_notifications_shared_examples.rb
index 2228e872926b053eb7a5e3abae4aff14bde51bc1..7c34c7b49777b2813af59afc4a0bee6b76a133e6 100644
--- a/spec/support/shared_examples/slack_mattermost_notifications_shared_examples.rb
+++ b/spec/support/shared_examples/slack_mattermost_notifications_shared_examples.rb
@@ -245,6 +245,70 @@ RSpec.shared_examples 'slack or mattermost notifications' do
     end
   end
 
+  describe 'Push events' do
+    let(:user) { create(:user) }
+    let(:project) { create(:project, :repository, creator: user) }
+
+    before do
+      allow(chat_service).to receive_messages(
+        project: project,
+        service_hook: true,
+        webhook: webhook_url
+      )
+
+      WebMock.stub_request(:post, webhook_url)
+    end
+
+    context 'only notify for the default branch' do
+      context 'when enabled' do
+        before do
+          chat_service.notify_only_default_branch = true
+        end
+
+        it 'does not notify push events if they are not for the default branch' do
+          ref = "#{Gitlab::Git::BRANCH_REF_PREFIX}test"
+          push_sample_data = Gitlab::DataBuilder::Push.build(project, user, nil, nil, ref, [])
+
+          chat_service.execute(push_sample_data)
+
+          expect(WebMock).not_to have_requested(:post, webhook_url)
+        end
+
+        it 'notifies about push events for the default branch' do
+          push_sample_data = Gitlab::DataBuilder::Push.build_sample(project, user)
+
+          chat_service.execute(push_sample_data)
+
+          expect(WebMock).to have_requested(:post, webhook_url).once
+        end
+
+        it 'still notifies about pushed tags' do
+          ref = "#{Gitlab::Git::TAG_REF_PREFIX}test"
+          push_sample_data = Gitlab::DataBuilder::Push.build(project, user, nil, nil, ref, [])
+
+          chat_service.execute(push_sample_data)
+
+          expect(WebMock).to have_requested(:post, webhook_url).once
+        end
+      end
+
+      context 'when disabled' do
+        before do
+          chat_service.notify_only_default_branch = false
+        end
+
+        it 'notifies about all push events' do
+          ref = "#{Gitlab::Git::BRANCH_REF_PREFIX}test"
+          push_sample_data = Gitlab::DataBuilder::Push.build(project, user, nil, nil, ref, [])
+
+          chat_service.execute(push_sample_data)
+
+          expect(WebMock).to have_requested(:post, webhook_url).once
+        end
+      end
+    end
+  end
+
   describe "Note events" do
     let(:user) { create(:user) }
     let(:project) { create(:project, :repository, creator: user) }
@@ -394,23 +458,6 @@ RSpec.shared_examples 'slack or mattermost notifications' do
 
           expect(result).to be_falsy
         end
-
-        it 'does not notify push events if they are not for the default branch' do
-          ref = "#{Gitlab::Git::BRANCH_REF_PREFIX}test"
-          push_sample_data = Gitlab::DataBuilder::Push.build(project, user, nil, nil, ref, [])
-
-          chat_service.execute(push_sample_data)
-
-          expect(WebMock).not_to have_requested(:post, webhook_url)
-        end
-
-        it 'notifies about push events for the default branch' do
-          push_sample_data = Gitlab::DataBuilder::Push.build_sample(project, user)
-
-          chat_service.execute(push_sample_data)
-
-          expect(WebMock).to have_requested(:post, webhook_url).once
-        end
       end
 
       context 'when disabled' do