diff --git a/src/diff.c b/src/diff.c
index bc755038da01b695f577ead23a9213a8e1aede5a..305e68f413a68aa83c8e4455c9719b8d6142fe2a 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -794,6 +794,10 @@ diff_file(tmp_orig, tmp_new, tmp_diff)
 				+ STRLEN(tmp_diff) + STRLEN(p_srr) + 27));
 	if (cmd != NULL)
 	{
+	    /* We don't want $DIFF_OPTIONS to get in the way. */
+	    if (getenv("DIFF_OPTIONS"))
+		vim_setenv((char_u *)"DIFF_OPTIONS", (char_u *)"");
+
 	    /* Build the diff command and execute it.  Always use -a, binary
 	     * differences are of no use.  Ignore errors, diff returns
 	     * non-zero when differences have been found. */