diff --git a/fsharp-mode.el b/fsharp-mode.el
index d6bf7e8..2e3d5b5 100644
--- a/fsharp-mode.el
+++ b/fsharp-mode.el
@@ -214,6 +214,7 @@
           comment-end
           comment-column
           comment-start-skip
+          comment-indent-function
           parse-sexp-ignore-comments
           indent-region-function
           indent-line-function