diff --git a/cwltool/workflow.py b/cwltool/workflow.py
index 3f61cd521..8546ca72e 100644
--- a/cwltool/workflow.py
+++ b/cwltool/workflow.py
@@ -17,6 +17,7 @@
 )
 from uuid import UUID
 
+from mypy_extensions import mypyc_attr
 from ruamel.yaml.comments import CommentedMap
 from schema_salad.exceptions import ValidationException
 from schema_salad.sourceline import SourceLine, indent
@@ -66,6 +67,7 @@ def default_make_tool(toolpath_object: CommentedMap, loadingContext: LoadingCont
 context.default_make_tool = default_make_tool
 
 
+@mypyc_attr(serializable=True)
 class Workflow(Process):
     def __init__(
         self,
diff --git a/tests/test_subclass_mypyc.py b/tests/test_subclass_mypyc.py
index 9f302fead..bb138cdc5 100644
--- a/tests/test_subclass_mypyc.py
+++ b/tests/test_subclass_mypyc.py
@@ -15,6 +15,7 @@
 from cwltool.context import LoadingContext, RuntimeContext
 from cwltool.stdfsaccess import StdFsAccess
 from cwltool.update import INTERNAL_VERSION
+from cwltool.workflow import Workflow
 
 from .test_anon_types import snippet
 
@@ -41,6 +42,16 @@ class TestExprTool(ExpressionTool):
     assert a.test is False
 
 
+@pytest.mark.parametrize("snippet", snippet)
+def test_pickle_unpickle_workflow(snippet: CommentedMap) -> None:
+    """We can pickle & unpickle a Workflow."""
+
+    a = Workflow(snippet, LoadingContext())
+    stream = pickle.dumps(a)
+    assert stream
+    assert pickle.loads(stream)
+
+
 def test_serialize_builder() -> None:
     """We can pickle Builder."""
     runtime_context = RuntimeContext()