diff --git a/builtin/merge-recursive.c b/builtin/merge-recursive.c
index 03b5100cfa..17aa4db37a 100644
--- a/builtin/merge-recursive.c
+++ b/builtin/merge-recursive.c
@@ -38,7 +38,8 @@ int cmd_merge_recursive(int argc,
 	if (argv[0] && ends_with(argv[0], "-subtree"))
 		o.subtree_shift = "";
 
-	if (argc == 2 && !strcmp(argv[1], "-h")) {
+	if (argc == 2 && (!strcmp(argv[1], "-h") ||
+			  !strcmp(argv[1], "--help-all"))) {
 		struct strbuf msg = STRBUF_INIT;
 		strbuf_addf(&msg, builtin_merge_recursive_usage, argv[0]);
 		show_usage_if_asked(argc, argv, msg.buf);
diff --git a/git.c b/git.c
index 83eac0aeab..958796d0b4 100644
--- a/git.c
+++ b/git.c
@@ -445,7 +445,7 @@ static int run_builtin(struct cmd_struct *p, int argc, const char **argv, struct
 	const char *prefix;
 	int run_setup = (p->option & (RUN_SETUP | RUN_SETUP_GENTLY));
 
-	help = argc == 2 && !strcmp(argv[1], "-h");
+	help = argc == 2 && (!strcmp(argv[1], "-h") || !strcmp(argv[1], "--help-all"));
 	if (help && (run_setup & RUN_SETUP))
 		/* demote to GENTLY to allow 'git cmd -h' outside repo */
 		run_setup = RUN_SETUP_GENTLY;
diff --git a/parse-options.c b/parse-options.c
index 9e7cb75192..992ec9631f 100644
--- a/parse-options.c
+++ b/parse-options.c
@@ -953,10 +953,16 @@ static void free_preprocessed_options(struct option *options)
 	free(options);
 }
 
+#define USAGE_NORMAL 0
+#define USAGE_FULL 1
+#define USAGE_TO_STDOUT 0
+#define USAGE_TO_STDERR 1
+
 static enum parse_opt_result usage_with_options_internal(struct parse_opt_ctx_t *,
 							 const char * const *,
 							 const struct option *,
-							 int, int);
+							 int full_usage,
+							 int usage_to_stderr);
 
 enum parse_opt_result parse_options_step(struct parse_opt_ctx_t *ctx,
 					 const struct option *options,
@@ -1088,7 +1094,8 @@ enum parse_opt_result parse_options_step(struct parse_opt_ctx_t *ctx,
 		}
 
 		if (internal_help && !strcmp(arg + 2, "help-all"))
-			return usage_with_options_internal(ctx, usagestr, options, 1, 0);
+			return usage_with_options_internal(ctx, usagestr, options,
+							   USAGE_FULL, USAGE_TO_STDOUT);
 		if (internal_help && !strcmp(arg + 2, "help"))
 			goto show_usage;
 		switch (parse_long_opt(ctx, arg + 2, options)) {
@@ -1129,7 +1136,8 @@ unknown:
 	return PARSE_OPT_DONE;
 
  show_usage:
-	return usage_with_options_internal(ctx, usagestr, options, 0, 0);
+	return usage_with_options_internal(ctx, usagestr, options,
+					   USAGE_NORMAL, USAGE_TO_STDOUT);
 }
 
 int parse_options_end(struct parse_opt_ctx_t *ctx)
@@ -1444,7 +1452,8 @@ static enum parse_opt_result usage_with_options_internal(struct parse_opt_ctx_t
 void NORETURN usage_with_options(const char * const *usagestr,
 			const struct option *opts)
 {
-	usage_with_options_internal(NULL, usagestr, opts, 0, 1);
+	usage_with_options_internal(NULL, usagestr, opts,
+				    USAGE_NORMAL, USAGE_TO_STDERR);
 	exit(129);
 }
 
@@ -1452,9 +1461,16 @@ void show_usage_with_options_if_asked(int ac, const char **av,
 				      const char * const *usagestr,
 				      const struct option *opts)
 {
-	if (ac == 2 && !strcmp(av[1], "-h")) {
-		usage_with_options_internal(NULL, usagestr, opts, 0, 0);
-		exit(129);
+	if (ac == 2) {
+		if (!strcmp(av[1], "-h")) {
+			usage_with_options_internal(NULL, usagestr, opts,
+						    USAGE_NORMAL, USAGE_TO_STDOUT);
+			exit(129);
+		} else if (!strcmp(av[1], "--help-all")) {
+			usage_with_options_internal(NULL, usagestr, opts,
+						    USAGE_FULL, USAGE_TO_STDOUT);
+			exit(129);
+		}
 	}
 }
 
diff --git a/t/t1517-outside-repo.sh b/t/t1517-outside-repo.sh
index 5ce0ceb176..1c69d52c76 100755
--- a/t/t1517-outside-repo.sh
+++ b/t/t1517-outside-repo.sh
@@ -133,6 +133,10 @@ do
 		test_expect_code 129 nongit git $cmd -h >usage &&
 		test_grep "[Uu]sage: git $cmd " usage
 	'
+	test_$expect_outcome $prereq "'git $cmd --help-all' outside a repository" '
+		test_expect_code 129 nongit git $cmd --help-all >usage &&
+		test_grep "[Uu]sage: git $cmd " usage
+	'
 done
 
 test_expect_success 'fmt-merge-msg does not crash with -h' '
diff --git a/usage.c b/usage.c
index 81913236a4..4c245ba0cb 100644
--- a/usage.c
+++ b/usage.c
@@ -192,7 +192,8 @@ static void show_usage_if_asked_helper(const char *err, ...)
 
 void show_usage_if_asked(int ac, const char **av, const char *err)
 {
-	if (ac == 2 && !strcmp(av[1], "-h"))
+	if (ac == 2 && (!strcmp(av[1], "-h") ||
+			!strcmp(av[1], "--help-all")))
 		show_usage_if_asked_helper(err);
 }