diff --git a/CHANGELOG.md b/CHANGELOG.md
index de7dbe3..fb82e1d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,11 @@
 Changelog
 =========
 
+## Unreleased
+
+- Fix bug: type annotations were not used because ``py.typed`` was not always
+  installed.
+
 ## v3.3.0 - 2022/03/23
 
 - Introduce type annotations for common APIs
diff --git a/setup.py b/setup.py
index fd86ef2..7c11d5d 100644
--- a/setup.py
+++ b/setup.py
@@ -48,6 +48,7 @@ def get_version(version):
         "rules.templatetags",
         "rules.contrib",
     ],
+    include_package_data=True,
     classifiers=[
         "Development Status :: 5 - Production/Stable",
         "Environment :: Web Environment",