diff --git a/pyproject.toml b/pyproject.toml
index a0a5f4d..0dc076d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -17,6 +17,7 @@ classifiers = [
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
+    "Typing :: Typed",
 ]
 license = "Apache-2.0"
 
diff --git a/src/spdx_python_model/py.typed b/src/spdx_python_model/py.typed
new file mode 100644
index 0000000..18615b1
--- /dev/null
+++ b/src/spdx_python_model/py.typed
@@ -0,0 +1 @@
+# PEP 561: Type hints marker