diff --git a/MANIFEST.in b/MANIFEST.in
index 6c0b223..6bfc3e3 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -1,5 +1,6 @@
 include cwcwidth/_impl.pyx cwcwidth/wcwidth.c cwcwidth/wcwidth_compat.h
 include cwcwidth/_impl.pyi cwcwidth/py.typed
+recursive-include tests *.py
 include CHANGELOG.md
 exclude .gitignore
 prune .github