diff --git a/config/feature_flags/gitlab_com_derisk/skip_reference_existence_check_for_child_pipelines.yml b/config/feature_flags/gitlab_com_derisk/skip_reference_existence_check_for_child_pipelines.yml
new file mode 100644
index 0000000000000000000000000000000000000000..32e90b62996bde02b5f552e50c121da31a889ff9
--- /dev/null
+++ b/config/feature_flags/gitlab_com_derisk/skip_reference_existence_check_for_child_pipelines.yml
@@ -0,0 +1,10 @@
+---
+name: skip_reference_existence_check_for_child_pipelines
+description: Skip reference existence check for child pipelines
+feature_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/428852
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/204279
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/569488
+milestone: '18.4'
+group: group::pipeline execution
+type: gitlab_com_derisk
+default_enabled: false
diff --git a/lib/gitlab/ci/pipeline/chain/validate/repository.rb b/lib/gitlab/ci/pipeline/chain/validate/repository.rb
index 7977ce904431720919a3ae9b8404e9125cdf5fe7..3440063ad483032ca8577a5ef3ed12d75def86e4 100644
--- a/lib/gitlab/ci/pipeline/chain/validate/repository.rb
+++ b/lib/gitlab/ci/pipeline/chain/validate/repository.rb
@@ -9,7 +9,10 @@ class Repository < Chain::Base
             include Chain::Helpers
 
             def perform!
-              unless @command.branch_exists? || @command.tag_exists? || @command.merge_request_ref_exists?
+              unless skip_reference_check? ||
+                  @command.branch_exists? ||
+                  @command.tag_exists? ||
+                  @command.merge_request_ref_exists?
                 return error('Reference not found')
               end
 
@@ -25,6 +28,18 @@ def perform!
             def break?
               @pipeline.errors.any?
             end
+
+            private
+
+            def skip_reference_check?
+              # Like jobs, child pipelines rely on the parent pipeline's
+              # reference validation. This is safe because they use exactly the
+              # same reference and SHA, and, thanks to a keep-around reference
+              # to the associated commit, allows for execution even after the
+              # ref has been deleted from the repository.
+              @pipeline.parent_pipeline? && Feature.enabled?(:skip_reference_existence_check_for_child_pipelines,
+                project)
+            end
           end
         end
       end
diff --git a/spec/lib/gitlab/ci/pipeline/chain/validate/repository_spec.rb b/spec/lib/gitlab/ci/pipeline/chain/validate/repository_spec.rb
index feedef18dcd23ffbbc447f6fdd8f755f924530cb..623914774a4230778e41c3931e0c6fb40274c029 100644
--- a/spec/lib/gitlab/ci/pipeline/chain/validate/repository_spec.rb
+++ b/spec/lib/gitlab/ci/pipeline/chain/validate/repository_spec.rb
@@ -42,6 +42,42 @@
       expect(pipeline.errors.to_a)
         .to include 'Reference not found'
     end
+
+    context 'when child pipeline' do
+      let(:pipeline) { build_stubbed(:ci_pipeline, source: :parent_pipeline) }
+
+      let(:command) do
+        Gitlab::Ci::Pipeline::Chain::Command.new(
+          project: project, current_user: user, origin_ref: 'something', checkout_sha: project.commit.id)
+      end
+
+      it 'does not break the chain' do
+        expect(step.break?).to be false
+      end
+
+      it 'does not append pipeline errors' do
+        expect(pipeline.errors).to be_empty
+      end
+
+      it 'skips reference validation' do
+        expect(command).not_to receive(:branch_exists?)
+        expect(command).not_to receive(:tag_exists?)
+        expect(command).not_to receive(:merge_request_ref_exists?)
+
+        step.perform!
+      end
+
+      context 'when FF skip_reference_existence_check_for_child_pipelines is disabled' do
+        before_all do
+          stub_feature_flags(skip_reference_existence_check_for_child_pipelines: false)
+        end
+
+        it 'breaks the chain and adds a "Reference not found" error' do
+          expect(step.break?).to be true
+          expect(pipeline.errors.to_a).to include 'Reference not found'
+        end
+      end
+    end
   end
 
   context 'when origin ref is a merge request ref' do