diff --git a/Modules/_sre/sre.c b/Modules/_sre/sre.c
index fdf00e6499cb6b..4e97101b699876 100644
--- a/Modules/_sre/sre.c
+++ b/Modules/_sre/sre.c
@@ -1946,7 +1946,7 @@ _validate_inner(SRE_CODE *code, SRE_CODE *end, Py_ssize_t groups)
                sre_match() code is robust even if they don't, and the worst
                you can get is nonsensical match results. */
             GET_ARG;
-            if (arg > 2 * (size_t)groups + 1) {
+            if (arg >= 2 * (size_t)groups) {
                 VTRACE(("arg=%d, groups=%d\n", (int)arg, (int)groups));
                 FAIL;
             }