diff --git a/.hgignore b/.hgignore
--- a/.hgignore
+++ b/.hgignore
@@ -52,6 +52,7 @@
 .idea/*
 .asv/*
 .pytype/*
+.mypy_cache
 i18n/hg.pot
 locale/*/LC_MESSAGES/hg.mo
 hgext/__index__.py