diff --git a/src/Cake.Common.Tests/Unit/Build/GitLabCI/Data/GitLabCIBuildInfoTests.cs b/src/Cake.Common.Tests/Unit/Build/GitLabCI/Data/GitLabCIBuildInfoTests.cs
index 86ebe58d8e..14b9ace302 100644
--- a/src/Cake.Common.Tests/Unit/Build/GitLabCI/Data/GitLabCIBuildInfoTests.cs
+++ b/src/Cake.Common.Tests/Unit/Build/GitLabCI/Data/GitLabCIBuildInfoTests.cs
@@ -2,7 +2,9 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using Cake.Common.Build.GitLabCI.Data;
 using Cake.Common.Tests.Fixtures.Build;
+using NSubstitute;
 using Xunit;
 
 namespace Cake.Common.Tests.Unit.Build.GitLabCI.Data
@@ -362,5 +364,41 @@ public void Should_Return_Correct_Value()
                 Assert.Equal(42, result);
             }
         }
+
+        public sealed class TheSourceProperty
+        {
+            // Values taken from https://docs.gitlab.com/ee/ci/jobs/job_rules.html#ci_pipeline_source-predefined-variable
+            [Theory]
+            [InlineData("", null)]
+            [InlineData("unknown_source", null)]
+            [InlineData("api", GitLabCIPipelineSource.Api)]
+            [InlineData("chat", GitLabCIPipelineSource.Chat)]
+            [InlineData("external", GitLabCIPipelineSource.External)]
+            [InlineData("external_pull_request_event", GitLabCIPipelineSource.ExternalPullRequestEvent)]
+            [InlineData("merge_request_event", GitLabCIPipelineSource.MergeRequestEvent)]
+            [InlineData("ondemand_dast_scan", GitLabCIPipelineSource.OnDemandDastScan)]
+            [InlineData("ondemand_dast_validation", GitLabCIPipelineSource.OnDemandDastValidation)]
+            [InlineData("parent_pipeline", GitLabCIPipelineSource.ParentPipeline)]
+            [InlineData("pipeline", GitLabCIPipelineSource.Pipeline)]
+            [InlineData("push", GitLabCIPipelineSource.Push)]
+            [InlineData("schedule", GitLabCIPipelineSource.Schedule)]
+            [InlineData("security_orchestration_policy", GitLabCIPipelineSource.SecurityOrchestrationPolicy)]
+            [InlineData("trigger", GitLabCIPipelineSource.Trigger)]
+            [InlineData("web", GitLabCIPipelineSource.Web)]
+            [InlineData("webide", GitLabCIPipelineSource.WebIde)]
+            public void Should_Return_Correct_Value(string pipelineSourceEnvironmentVariable, GitLabCIPipelineSource? expectedSource)
+            {
+                // Given
+                var fixture = new GitLabCIInfoFixture();
+                fixture.Environment.GetEnvironmentVariable("CI_PIPELINE_SOURCE").Returns(pipelineSourceEnvironmentVariable);
+                var info = fixture.CreateBuildInfo();
+
+                // When
+                var result = info.Source;
+
+                // Then
+                Assert.Equal(expectedSource, result);
+            }
+        }
     }
 }
diff --git a/src/Cake.Common/Build/GitLabCI/Data/GitLabCIBuildInfo.cs b/src/Cake.Common/Build/GitLabCI/Data/GitLabCIBuildInfo.cs
index d97d18c5ef..c811bcf48d 100644
--- a/src/Cake.Common/Build/GitLabCI/Data/GitLabCIBuildInfo.cs
+++ b/src/Cake.Common/Build/GitLabCI/Data/GitLabCIBuildInfo.cs
@@ -131,5 +131,13 @@ public GitLabCIBuildInfo(ICakeEnvironment environment)
         /// The email address of the user.
         /// </value>
         public string UserEmail => GetEnvironmentString("GITLAB_USER_EMAIL");
+
+        /// <summary>
+        /// Gets how the pipeline was triggered.
+        /// </summary>
+        /// <value>
+        /// The trigger of the pipeline as <see cref="GitLabCIPipelineSource"/> or <c>null</c> if the trigger could not be determined.
+        /// </value>
+        public GitLabCIPipelineSource? Source => GetEnvironmentEnum<GitLabCIPipelineSource>("CI_PIPELINE_SOURCE");
     }
 }
diff --git a/src/Cake.Common/Build/GitLabCI/Data/GitLabCIPipelineSource.cs b/src/Cake.Common/Build/GitLabCI/Data/GitLabCIPipelineSource.cs
new file mode 100644
index 0000000000..0d2b3ea8d6
--- /dev/null
+++ b/src/Cake.Common/Build/GitLabCI/Data/GitLabCIPipelineSource.cs
@@ -0,0 +1,91 @@
+using System.Runtime.Serialization;
+
+namespace Cake.Common.Build.GitLabCI.Data;
+
+/// <summary>
+/// Enumerates possible triggers of a GitLab CI pipeline.
+/// </summary>
+/// <seealso href="https://docs.gitlab.com/ee/ci/jobs/job_rules.html#ci_pipeline_source-predefined-variable"> CI_PIPELINE_SOURCE predefined variable (GitLab Documentation)</seealso>
+public enum GitLabCIPipelineSource
+{
+    /// <summary>
+    /// Pipeline var triggered by the pipelines API.
+    /// </summary>
+    Api,
+
+    /// <summary>
+    /// Pipeline was created using a GitLab ChatOps command.
+    /// </summary>
+    Chat,
+
+    /// <summary>
+    /// Pipeline was created using a CI service other than GitLab
+    /// </summary>
+    External,
+
+    /// <summary>
+    /// Pipeline was created because an external pull request on GitHub was created or updated.
+    /// </summary>
+    [EnumMember(Value = "external_pull_request_event")]
+    ExternalPullRequestEvent,
+
+    /// <summary>
+    /// Pipeline was created because a merge request was created or updated.
+    /// </summary>
+    [EnumMember(Value = "merge_request_event")]
+    MergeRequestEvent,
+
+    /// <summary>
+    /// Pipeline is an on-demand DAST scan pipeline.
+    /// </summary>
+    [EnumMember(Value = "ondemand_dast_scan")]
+    OnDemandDastScan,
+
+    /// <summary>
+    /// Pipeline is an on-demand DAST validation pipeline.
+    /// </summary>
+    [EnumMember(Value = "ondemand_dast_validation")]
+    OnDemandDastValidation,
+
+    /// <summary>
+    /// Pipeline was created by a parent pipeline.
+    /// </summary>
+    [EnumMember(Value = "parent_pipeline")]
+    ParentPipeline,
+
+    /// <summary>
+    /// Pipeline was created by another pipeline
+    /// </summary>
+    Pipeline,
+
+    /// <summary>
+    /// Pipelune was triggered by a Git push event.
+    /// </summary>
+    Push,
+
+    /// <summary>
+    /// Pipeline was triggered by a schedule.
+    /// </summary>
+    Schedule,
+
+    /// <summary>
+    /// Pipeline is a security orchestration policy pipeline.
+    /// </summary>
+    [EnumMember(Value = "security_orchestration_policy")]
+    SecurityOrchestrationPolicy,
+
+    /// <summary>
+    /// Pipeline was created using a trigger token.
+    /// </summary>
+    Trigger,
+
+    /// <summary>
+    /// Pipeline was created by selecting <i>New Pipeline</i> in the GitLab UI.
+    /// </summary>
+    Web,
+
+    /// <summary>
+    /// Pipeline was created using the Web IDE.
+    /// </summary>
+    WebIde
+}
\ No newline at end of file
diff --git a/src/Cake.Common/Build/GitLabCI/GitLabCIInfo.cs b/src/Cake.Common/Build/GitLabCI/GitLabCIInfo.cs
index bcbb7a7251..03a3bd2dc7 100644
--- a/src/Cake.Common/Build/GitLabCI/GitLabCIInfo.cs
+++ b/src/Cake.Common/Build/GitLabCI/GitLabCIInfo.cs
@@ -3,6 +3,9 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
+using System.Linq;
+using System.Reflection;
+using System.Runtime.Serialization;
 using Cake.Core;
 
 namespace Cake.Common.Build.GitLabCI
@@ -99,5 +102,48 @@ protected bool GetEnvironmentBoolean(string primaryVariable, string secondaryVar
         {
             return GetEnvironmentBoolean(primaryVariable) ? GetEnvironmentBoolean(primaryVariable) : GetEnvironmentBoolean(secondaryVariable);
         }
+
+        /// <summary>
+        /// Gets an environment variable as an enum.
+        /// </summary>
+        /// <remarks>
+        /// By default, the environment variable value is presumed to be identical to the enum value name.
+        /// To define a mapping between environment variable value and enum name, apply the <see cref="EnumMemberAttribute"/> attribue in the enum definition.
+        /// <para>
+        /// Parsing is case-insensitive.
+        /// </para>
+        /// </remarks>
+        /// <param name="variable">The primary environment variable name.</param>
+        /// <typeparam name="TEnum">The type of the enum to return.</typeparam>
+        /// <returns>
+        /// The environment variable value converted to the corresponding value of <typeparamref name="TEnum"/> or
+        /// <c>null</c> if the variable is not set or the value could not be converted to the the specified enum type.
+        /// </returns>
+        protected TEnum? GetEnvironmentEnum<TEnum>(string variable) where TEnum : struct, Enum
+        {
+            var value = GetEnvironmentString(variable);
+            if (!string.IsNullOrWhiteSpace(value))
+            {
+                // Instead of using Enum.TryParse(), enumerate the enum fields using reflection.
+                // This defining enums where the environment variable value differs from the name of the corresponding enum member:
+                // - If the enum member has a [EnumMember] attribute, use the value defined by the attribute instead of the enum member name
+                // - Otherwise, use the enum member name (matching the behavior of Enum.TryParse())
+                foreach (var field in typeof(TEnum).GetFields().Where(fi => fi.FieldType == typeof(TEnum)))
+                {
+                    var enumMemberName = field.Name;
+                    if (field.GetCustomAttribute<EnumMemberAttribute>() is { Value: { } customName } && !string.IsNullOrEmpty(customName))
+                    {
+                        enumMemberName = customName;
+                    }
+
+                    if (StringComparer.OrdinalIgnoreCase.Equals(enumMemberName, value))
+                    {
+                        return (TEnum?)field.GetValue(null);
+                    }
+                }
+            }
+
+            return null;
+        }
     }
 }
\ No newline at end of file