diff --git a/app/finders/ci/pipelines_finder.rb b/app/finders/ci/pipelines_finder.rb
index b3aefe6fa448b4440e56ada6958960694828ba67..a17103cd48a2816e4eb1a711d9f1418d1147f68c 100644
--- a/app/finders/ci/pipelines_finder.rb
+++ b/app/finders/ci/pipelines_finder.rb
@@ -25,8 +25,7 @@ def initialize(project, current_user, params = {})
     def execute
       return Ci::Pipeline.none unless Ability.allowed?(current_user, :read_pipeline, project)
 
-      items = pipelines
-      items = items.no_child unless params[:iids].present?
+      items = prefiltered_pipelines
       items = by_iids(items)
       items = by_scope(items)
       items = by_status(items)
@@ -63,6 +62,13 @@ def tags
       project.repository.tag_names
     end
 
+    def prefiltered_pipelines
+      return pipelines if params[:iids].present?
+      return pipelines if params[:source] == 'parent_pipeline'
+
+      pipelines.no_child
+    end
+
     def by_iids(items)
       if params[:iids].present?
         items.for_iid(params[:iids])
diff --git a/doc/api/pipelines.md b/doc/api/pipelines.md
index b4766aa7b9fa5bdf397c0b5e16fd5bfea3c7f586..93b4a07773db89a83ab19cc3bfeac1a2dbe38d06 100644
--- a/doc/api/pipelines.md
+++ b/doc/api/pipelines.md
@@ -24,9 +24,12 @@ Read more on [pagination](rest/index.md#pagination).
 > - `name` in request [introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/115310) in 15.11 [with a flag](../administration/feature_flags.md) named `pipeline_name_search`. Disabled by default.
 > - `name` in response [generally available](https://gitlab.com/gitlab-org/gitlab/-/issues/398131) in GitLab 16.3. Feature flag `pipeline_name_in_api` removed.
 > - `name` in request [generally available](https://gitlab.com/gitlab-org/gitlab/-/issues/385864) in GitLab 16.9. Feature flag `pipeline_name_search` removed.
+> - Support for returning child pipelines with `source` set to `parent_pipeline` [introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/39503) in GitLab 17.0.
 
-List pipelines in a project. Child pipelines are not included in the results,
-but you can [get child pipeline](pipelines.md#get-a-single-pipeline) individually.
+List pipelines in a project.
+
+By default, [child pipelines](../ci/pipelines/downstream_pipelines.md#parent-child-pipelines)
+are not included in the results. To return child pipelines, set `source` to `parent_pipeline`.
 
 ```plaintext
 GET /projects/:id/pipelines
diff --git a/spec/finders/ci/pipelines_finder_spec.rb b/spec/finders/ci/pipelines_finder_spec.rb
index 7a94c8191f5547e13203ce38f8491892d38fecd4..bb3b603976b9a7ae5b196d54b759cb8e9b731cff 100644
--- a/spec/finders/ci/pipelines_finder_spec.rb
+++ b/spec/finders/ci/pipelines_finder_spec.rb
@@ -75,6 +75,14 @@
       it 'filters out child pipelines and shows only the parents by default' do
         is_expected.to eq([parent_pipeline])
       end
+
+      context 'when source is parent_pipeline' do
+        let(:params) { { source: 'parent_pipeline' } }
+
+        it 'does not filter out child pipelines' do
+          is_expected.to eq([child_pipeline])
+        end
+      end
     end
 
     Ci::HasStatus::AVAILABLE_STATUSES.each do |target|