diff --git a/.gitignore b/.gitignore
index fead3cd9c1980bbefe11706d32bd576c5e722dce..3b3e228084db550cd791781fc0656f91b35a2b97 100644
--- a/.gitignore
+++ b/.gitignore
@@ -22,3 +22,4 @@ Makefile.coq.conf
 .Makefile.coq.d
 Makefile.package.*
 .Makefile.package.*
+_opam