diff --git a/app/models/ci/pipeline.rb b/app/models/ci/pipeline.rb
index ea7331cb27f027d31bf57b879c08513fa05d962a..2d40f8012a3ef22d0a4677c0c1bde96b51375e8e 100644
--- a/app/models/ci/pipeline.rb
+++ b/app/models/ci/pipeline.rb
@@ -393,7 +393,8 @@ module Ci
     def predefined_variables
       [
         { key: 'CI_PIPELINE_ID', value: id.to_s, public: true },
-        { key: 'CI_CONFIG_PATH', value: ci_yaml_file_path, public: true }
+        { key: 'CI_CONFIG_PATH', value: ci_yaml_file_path, public: true },
+        { key: 'CI_PIPELINE_SOURCE', value: source.to_s, public: true }
       ]
     end
 
diff --git a/changelogs/unreleased/zj-add-pipeline-source-variable.yml b/changelogs/unreleased/zj-add-pipeline-source-variable.yml
new file mode 100644
index 0000000000000000000000000000000000000000..5d98cd8086aac0d3fdc02368460200211731fb94
--- /dev/null
+++ b/changelogs/unreleased/zj-add-pipeline-source-variable.yml
@@ -0,0 +1,5 @@
+---
+title: Add CI_PIPELINE_SOURCE variable on CI Jobs
+merge_request:
+author:
+type: added
diff --git a/doc/ci/variables/README.md b/doc/ci/variables/README.md
index 22e7f6879ed7e13d20c130b6a2d9cfa324049bef..e55a92dbb71fbfe551f1a893c5f3bdfe8a6ae100 100644
--- a/doc/ci/variables/README.md
+++ b/doc/ci/variables/README.md
@@ -57,6 +57,7 @@ future GitLab releases.**
 | **CI_RUNNER_TAGS**              | 8.10   | 0.5    | The defined runner tags |
 | **CI_PIPELINE_ID**              | 8.10   | 0.5    | The unique id of the current pipeline that GitLab CI uses internally |
 | **CI_PIPELINE_TRIGGERED**       | all    | all    | The flag to indicate that job was [triggered] |
+| **CI_PIPELINE_SOURCE**          | 10.0   | all    | The source for this pipeline, one of: push, web, trigger, schedule, api, external. Pipelines created before 9.5 will have unknown as source |
 | **CI_PROJECT_DIR**              | all    | all    | The full path where the repository is cloned and where the job is run |
 | **CI_PROJECT_ID**               | all    | all    | The unique id of the current project that GitLab CI uses internally |
 | **CI_PROJECT_NAME**             | 8.10   | 0.5    | The project name that is currently being built (actually it is project folder name) |
diff --git a/spec/models/ci/pipeline_spec.rb b/spec/models/ci/pipeline_spec.rb
index ac75c6501ee2515fd8e0e1898f72b56a684c5eef..b84e3ff18e8e2594b0cca48269d7eacf8ad091b6 100644
--- a/spec/models/ci/pipeline_spec.rb
+++ b/spec/models/ci/pipeline_spec.rb
@@ -2,7 +2,7 @@ require 'spec_helper'
 
 describe Ci::Pipeline, :mailer do
   let(:user) { create(:user) }
-  let(:project) { create(:project) }
+  set(:project) { create(:project) }
 
   let(:pipeline) do
     create(:ci_empty_pipeline, status: :created, project: project)
@@ -159,6 +159,18 @@ describe Ci::Pipeline, :mailer do
     end
   end
 
+  describe '#predefined_variables' do
+    subject { pipeline.predefined_variables }
+
+    it { is_expected.to be_an(Array) }
+
+    it 'includes the defined keys' do
+      keys = subject.map { |v| v[:key] }
+
+      expect(keys).to include('CI_PIPELINE_ID', 'CI_CONFIG_PATH', 'CI_PIPELINE_SOURCE')
+    end
+  end
+
   describe '#auto_canceled?' do
     subject { pipeline.auto_canceled? }