diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index c1c40b516d..ec4996282e 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -455,9 +455,12 @@ static int bisect_start(struct bisect_terms *terms, int no_checkout,
 			no_checkout = 1;
 		} else if (!strcmp(arg, "--term-good") ||
 			 !strcmp(arg, "--term-old")) {
+			i++;
+			if (argc <= i)
+				return error(_("'' is not a valid term"));
 			must_write_terms = 1;
 			free((void *) terms->term_good);
-			terms->term_good = xstrdup(argv[++i]);
+			terms->term_good = xstrdup(argv[i]);
 		} else if (skip_prefix(arg, "--term-good=", &arg) ||
 			   skip_prefix(arg, "--term-old=", &arg)) {
 			must_write_terms = 1;
@@ -465,16 +468,18 @@ static int bisect_start(struct bisect_terms *terms, int no_checkout,
 			terms->term_good = xstrdup(arg);
 		} else if (!strcmp(arg, "--term-bad") ||
 			 !strcmp(arg, "--term-new")) {
+			i++;
+			if (argc <= i)
+				return error(_("'' is not a valid term"));
 			must_write_terms = 1;
 			free((void *) terms->term_bad);
-			terms->term_bad = xstrdup(argv[++i]);
+			terms->term_bad = xstrdup(argv[i]);
 		} else if (skip_prefix(arg, "--term-bad=", &arg) ||
 			   skip_prefix(arg, "--term-new=", &arg)) {
 			must_write_terms = 1;
 			free((void *) terms->term_bad);
 			terms->term_bad = xstrdup(arg);
-		} else if (starts_with(arg, "--") &&
-			 !one_of(arg, "--term-good", "--term-bad", NULL)) {
+		} else if (starts_with(arg, "--")) {
 			return error(_("unrecognized option: '%s'"), arg);
 		} else {
 			char *commit_id = xstrfmt("%s^{commit}", arg);
diff --git a/t/t6030-bisect-porcelain.sh b/t/t6030-bisect-porcelain.sh
index ac31faefa1..36d9b2b2e4 100755
--- a/t/t6030-bisect-porcelain.sh
+++ b/t/t6030-bisect-porcelain.sh
@@ -866,7 +866,9 @@ test_expect_success 'bisect cannot mix terms' '
 
 test_expect_success 'bisect terms rejects invalid terms' '
 	git bisect reset &&
+	test_must_fail git bisect start --term-good &&
 	test_must_fail git bisect start --term-good invalid..term &&
+	test_must_fail git bisect start --term-bad &&
 	test_must_fail git bisect terms --term-bad invalid..term &&
 	test_must_fail git bisect terms --term-good bad &&
 	test_must_fail git bisect terms --term-good old &&