diff --git a/task_test.go b/task_test.go
index 540e7ba8de..0a050812b7 100644
--- a/task_test.go
+++ b/task_test.go
@@ -2377,6 +2377,28 @@ func TestRunOnceSharedDeps(t *testing.T) {
 	assert.Contains(t, buff.String(), `task: [service-b:build] echo "build b"`)
 }
 
+func TestRunOnceGlobalInIncludedTaskfile(t *testing.T) {
+	t.Parallel()
+
+	const dir = "testdata/run_once_included"
+
+	var buff bytes.Buffer
+	e := task.NewExecutor(
+		task.WithDir(dir),
+		task.WithStdout(&buff),
+		task.WithStderr(&buff),
+		task.WithForceAll(true),
+	)
+	require.NoError(t, e.Setup())
+	require.NoError(t, e.Run(t.Context(), &task.Call{Task: "build"}))
+
+	// The included Taskfile sets `run: once` globally, so its build task should
+	// execute once even though both service-a and service-b depend on it.
+	assert.Equal(t, 1, strings.Count(buff.String(), `echo "build library"`))
+	assert.Contains(t, buff.String(), `task: [service-a] echo "build a"`)
+	assert.Contains(t, buff.String(), `task: [service-b] echo "build b"`)
+}
+
 func TestRunOnceSharedFailurePropagates(t *testing.T) {
 	t.Parallel()
 
diff --git a/taskfile/ast/taskfile.go b/taskfile/ast/taskfile.go
index 20b4476cd5..52260f1d4e 100644
--- a/taskfile/ast/taskfile.go
+++ b/taskfile/ast/taskfile.go
@@ -76,6 +76,13 @@ func (t1 *Taskfile) Merge(t2 *Taskfile, include *Include) error {
 			}
 		}
 	}
+	if t2.Run != "" {
+		for _, t := range t2.Tasks.All(nil) {
+			if t.Run == "" {
+				t.Run = t2.Run
+			}
+		}
+	}
 	t1.Vars.Merge(t2.Vars, include)
 	t1.Env.Merge(t2.Env, include)
 	return t1.Tasks.Merge(t2.Tasks, include, t1.Vars)
diff --git a/testdata/run_once_included/Taskfile.yml b/testdata/run_once_included/Taskfile.yml
new file mode 100644
index 0000000000..664c297872
--- /dev/null
+++ b/testdata/run_once_included/Taskfile.yml
@@ -0,0 +1,22 @@
+version: '3'
+
+includes:
+  library: ./library
+
+tasks:
+  build:
+    deps:
+      - service-a
+      - service-b
+
+  service-a:
+    deps:
+      - library:build
+    cmds:
+      - echo "build a"
+
+  service-b:
+    deps:
+      - library:build
+    cmds:
+      - echo "build b"
diff --git a/testdata/run_once_included/library/Taskfile.yml b/testdata/run_once_included/library/Taskfile.yml
new file mode 100644
index 0000000000..f135b1c1af
--- /dev/null
+++ b/testdata/run_once_included/library/Taskfile.yml
@@ -0,0 +1,8 @@
+version: '3'
+
+run: once
+
+tasks:
+  build:
+    cmds:
+      - echo "build library"