diff --git a/src/basic/escape.c b/src/basic/escape.c
index 79123536c0..e1771bf432 100644
--- a/src/basic/escape.c
+++ b/src/basic/escape.c
@@ -598,7 +598,7 @@ char* shell_maybe_quote(const char *s, ShellEscapeFlags flags) {
         return str_realloc(buf);
 }
 
-char* quote_command_line(char **argv, ShellEscapeFlags flags) {
+char* quote_command_line(char * const *argv, ShellEscapeFlags flags) {
         _cleanup_free_ char *result = NULL;
 
         assert(argv);
diff --git a/src/basic/escape.h b/src/basic/escape.h
index c42302c24e..3d8a1890cf 100644
--- a/src/basic/escape.h
+++ b/src/basic/escape.h
@@ -65,4 +65,4 @@ char* escape_non_printable_full(const char *str, size_t console_width, XEscapeFl
 
 char* shell_escape(const char *s, const char *bad);
 char* shell_maybe_quote(const char *s, ShellEscapeFlags flags);
-char* quote_command_line(char **argv, ShellEscapeFlags flags);
+char* quote_command_line(char * const *argv, ShellEscapeFlags flags);