diff --git a/Documentation/config/core.txt b/Documentation/config/core.txt
index c86b8c8408..bbe869c497 100644
--- a/Documentation/config/core.txt
+++ b/Documentation/config/core.txt
@@ -520,15 +520,28 @@ core.editor::
 	`GIT_EDITOR` is not set.  See linkgit:git-var[1].
 
 core.commentChar::
+core.commentString::
 	Commands such as `commit` and `tag` that let you edit
 	messages consider a line that begins with this character
 	commented, and removes them after the editor returns
-	(default '#'). Note that this option can take values larger than
-	a byte (whether a single multi-byte character, or you
-	could even go wild with a multi-character sequence).
+	(default '#').
 +
 If set to "auto", `git-commit` would select a character that is not
 the beginning character of any line in existing commit messages.
++
+Note that these two variables are aliases of each other, and in modern
+versions of Git you are free to use a string (e.g., `//` or `⁑⁕⁑`) with
+`commentChar`. Versions of Git prior to v2.45.0 will ignore
+`commentString` but will reject a value of `commentChar` that consists
+of more than a single ASCII byte. If you plan to use your config with
+older and newer versions of Git, you may want to specify both:
++
+    [core]
+    # single character for older versions
+    commentChar = "#"
+    # string for newer versions (which will override commentChar
+    # because it comes later in the file)
+    commentString = "//"
 
 core.filesRefLockTimeout::
 	The length of time, in milliseconds, to retry when trying to
diff --git a/config.c b/config.c
index 92c752ed9f..d12e0f34f1 100644
--- a/config.c
+++ b/config.c
@@ -1560,18 +1560,19 @@ static int git_default_core_config(const char *var, const char *value,
 	if (!strcmp(var, "core.editor"))
 		return git_config_string(&editor_program, var, value);
 
-	if (!strcmp(var, "core.commentchar")) {
+	if (!strcmp(var, "core.commentchar") ||
+	    !strcmp(var, "core.commentstring")) {
 		if (!value)
 			return config_error_nonbool(var);
 		else if (!strcasecmp(value, "auto"))
 			auto_comment_line_char = 1;
 		else if (value[0]) {
 			if (strchr(value, '\n'))
-				return error(_("core.commentChar cannot contain newline"));
+				return error(_("%s cannot contain newline"), var);
 			comment_line_str = xstrdup(value);
 			auto_comment_line_char = 0;
 		} else
-			return error(_("core.commentChar must have at least one character"));
+			return error(_("%s must have at least one character"), var);
 		return 0;
 	}
 
diff --git a/t/t0030-stripspace.sh b/t/t0030-stripspace.sh
index a161faf702..f10f42ff1e 100755
--- a/t/t0030-stripspace.sh
+++ b/t/t0030-stripspace.sh
@@ -401,14 +401,19 @@ test_expect_success 'strip comments with changed comment char' '
 	test -z "$(echo "; comment" | git -c core.commentchar=";" stripspace -s)"
 '
 
+test_expect_success 'strip comments with changed comment string' '
+	test ! -z "$(echo "// comment" | git -c core.commentchar=// stripspace)" &&
+	test -z "$(echo "// comment" | git -c core.commentchar="//" stripspace -s)"
+'
+
 test_expect_success 'newline as commentchar is forbidden' '
 	test_must_fail git -c core.commentChar="$LF" stripspace -s 2>err &&
-	grep "core.commentChar cannot contain newline" err
+	grep "core.commentchar cannot contain newline" err
 '
 
 test_expect_success 'empty commentchar is forbidden' '
 	test_must_fail git -c core.commentchar= stripspace -s 2>err &&
-	grep "core.commentChar must have at least one character" err
+	grep "core.commentchar must have at least one character" err
 '
 
 test_expect_success '-c with single line' '