diff --git a/Documentation/git-config.txt b/Documentation/git-config.txt
index e608d5ffef..af374ee2e0 100644
--- a/Documentation/git-config.txt
+++ b/Documentation/git-config.txt
@@ -9,9 +9,9 @@ git-config - Get and set repository or global options
 SYNOPSIS
 --------
 [verse]
-'git config' [<file-option>] [--type=<type>] [--comment=<value>] [--fixed-value] [--show-origin] [--show-scope] [-z|--null] <name> [<value> [<value-pattern>]]
-'git config' [<file-option>] [--type=<type>] [--comment=<value>] --add <name> <value>
-'git config' [<file-option>] [--type=<type>] [--comment=<value>] [--fixed-value] --replace-all <name> <value> [<value-pattern>]
+'git config' [<file-option>] [--type=<type>] [--comment=<message>] [--fixed-value] [--show-origin] [--show-scope] [-z|--null] <name> [<value> [<value-pattern>]]
+'git config' [<file-option>] [--type=<type>] [--comment=<message>] --add <name> <value>
+'git config' [<file-option>] [--type=<type>] [--comment=<message>] [--fixed-value] --replace-all <name> <value> [<value-pattern>]
 'git config' [<file-option>] [--type=<type>] [--show-origin] [--show-scope] [-z|--null] [--fixed-value] --get <name> [<value-pattern>]
 'git config' [<file-option>] [--type=<type>] [--show-origin] [--show-scope] [-z|--null] [--fixed-value] --get-all <name> [<value-pattern>]
 'git config' [<file-option>] [--type=<type>] [--show-origin] [--show-scope] [-z|--null] [--fixed-value] [--name-only] --get-regexp <name-regex> [<value-pattern>]
@@ -87,10 +87,11 @@ OPTIONS
 	values.  This is the same as providing '^$' as the `value-pattern`
 	in `--replace-all`.
 
---comment <value>::
-	Append a comment to new or modified lines. A '#' character will be
-	unconditionally prepended to the value. The value must not contain
-	linefeed characters (no multi-line comments are permitted).
+--comment <message>::
+	Append a comment at the end of new or modified lines.
+	Unless _<message>_ begins with "#", a string "# " (hash
+	followed by a space) is prepended to it. The _<message>_ must not
+	contain linefeed characters (no multi-line comments are permitted).
 
 --get::
 	Get the value for a given key (optionally filtered by a regex
diff --git a/builtin/config.c b/builtin/config.c
index c54e9941a5..e859a659f4 100644
--- a/builtin/config.c
+++ b/builtin/config.c
@@ -174,7 +174,7 @@ static struct option builtin_config_options[] = {
 	OPT_BOOL(0, "show-origin", &show_origin, N_("show origin of config (file, standard input, blob, command line)")),
 	OPT_BOOL(0, "show-scope", &show_scope, N_("show scope of config (worktree, local, global, system, command)")),
 	OPT_STRING(0, "default", &default_value, N_("value"), N_("with --get, use default value when missing entry")),
-	OPT_STRING(0, "comment", &comment, N_("value"), N_("human-readable comment string (# will be prepended automatically)")),
+	OPT_STRING(0, "comment", &comment, N_("value"), N_("human-readable comment string (# will be prepended as needed)")),
 	OPT_END(),
 };
 
@@ -800,9 +800,9 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 	}
 
 	if (comment &&
-		!(actions & (ACTION_ADD|ACTION_SET|ACTION_SET_ALL|ACTION_REPLACE_ALL))) {
-			error(_("--comment is only applicable to add/set/replace operations"));
-			usage_builtin_config();
+	    !(actions & (ACTION_ADD|ACTION_SET|ACTION_SET_ALL|ACTION_REPLACE_ALL))) {
+		error(_("--comment is only applicable to add/set/replace operations"));
+		usage_builtin_config();
 	}
 
 	/* check usage of --fixed-value */
@@ -841,6 +841,13 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 		flags |= CONFIG_FLAGS_FIXED_VALUE;
 	}
 
+	if (comment) {
+		if (strchr(comment, '\n'))
+			die(_("no multi-line comment allowed: '%s'"), comment);
+		if (comment[0] != '#')
+			comment = xstrfmt("# %s", comment);
+	}
+
 	if (actions & PAGING_ACTIONS)
 		setup_auto_pager("config", 1);
 
diff --git a/config.c b/config.c
index 2f3f6d123c..15019cb9a5 100644
--- a/config.c
+++ b/config.c
@@ -3043,12 +3043,9 @@ static ssize_t write_pair(int fd, const char *key, const char *value,
 			break;
 		}
 
-	if (comment) {
-		if (strchr(comment, '\n'))
-			die(_("multi-line comments are not permitted: '%s'"), comment);
-		else
-			strbuf_addf(&sb, "%s #%s\n", quote, comment);
-	} else
+	if (comment)
+		strbuf_addf(&sb, "%s %s\n", quote, comment);
+	else
 		strbuf_addf(&sb, "%s\n", quote);
 
 	ret = write_in_full(fd, sb.buf, sb.len);
@@ -3214,6 +3211,17 @@ int git_config_set_multivar_in_file_gently(const char *config_filename,
 	size_t contents_sz;
 	struct config_store_data store = CONFIG_STORE_INIT;
 
+	if (comment) {
+		/*
+		 * The front-end must have massaged the comment string
+		 * properly before calling us.
+		 */
+		if (strchr(comment, '\n'))
+			BUG("multi-line comments are not permitted: '%s'", comment);
+		if (comment[0] != '#')
+			BUG("comment should begin with '#': '%s'", comment);
+	}
+
 	/* parse-key returns negative; flip the sign to feed exit(3) */
 	ret = 0 - git_config_parse_key(key, &store.key, &store.baselen);
 	if (ret)
diff --git a/t/t1300-config.sh b/t/t1300-config.sh
index ac7b02e6b0..d5dfb45877 100755
--- a/t/t1300-config.sh
+++ b/t/t1300-config.sh
@@ -71,16 +71,17 @@ cat > expect << EOF
 [section]
 	Movie = BadPhysics
 	UPPERCASE = true
-	penguin = gentoo #Pygoscelis papua
-	disposition = peckish #find fish
-	foo = bar ## abc
+	penguin = gentoo # Pygoscelis papua
+	disposition = peckish # find fish
+	foo = bar #abc
 [Sections]
 	WhatEver = Second
 EOF
+
 test_expect_success 'append comments' '
 	git config --replace-all --comment="Pygoscelis papua" section.penguin gentoo &&
 	git config --comment="find fish" section.disposition peckish &&
-	git config --comment="# abc" section.foo bar &&
+	git config --comment="#abc" section.foo bar &&
 	test_cmp expect .git/config
 '