diff --git a/source/texk/web2c/luatexdir/font/texfont.c b/source/texk/web2c/luatexdir/font/texfont.c
index 496cb0838..16e8a5131 100644
--- a/source/texk/web2c/luatexdir/font/texfont.c
+++ b/source/texk/web2c/luatexdir/font/texfont.c
@@ -1878,7 +1878,7 @@ void read_expand_font(void)
/*tex
- Here's an old (sort of obsolete) letterspace-a-font helper. It does so by by
+ Here's an old (sort of obsolete) letterspace-a-font helper. It does so by
creating a virtual font.
*/
