diff --git a/icu4c/source/tools/ctestfw/ctest.c b/icu4c/source/tools/ctestfw/ctest.c
index ce930d8915..60ad173222 100644
--- a/icu4c/source/tools/ctestfw/ctest.c
+++ b/icu4c/source/tools/ctestfw/ctest.c
@@ -635,7 +635,7 @@ int processArgs(const TestNode* root,
 static void help ( const char *argv0 )
 {
     printf("Usage: %s [ -l ] [ -v ] [ -verbose] [-a] [ -all] [-n] [ -no_err_msg]\n"
-           "                [ -h ] [-t_info | -t_error | -t_warn | -t_verbose] [ /path/to/test ]\n",
+           "                [ -h ] [-t_info | -t_error | -t_warn | -t_verbose] [-tz [zone]] [ /path/to/test ]\n",
             argv0);
     printf("    -l  To get a list of test names\n");
     printf("    -e  to do exhaustive testing\n");
@@ -648,6 +648,9 @@ static void help ( const char *argv0 )
     printf("    -t_info | -t_error | -t_warn | -t_verbose  Enable ICU tracing\n");
     printf("    -no_err_msg (same as -n) \n");
     printf("    -r  repeat tests after calling u_cleanup \n");
+    /* NOTE: the -tz [zone] option is parsed by cintltst. I know, ugly. */
+    printf("    -tz [zone] To set default time zone.  If no zone is given\n"
+           "        then don't set default time zone (use host zone).\n");
     printf("    -[/subtest]  To run a subtest \n");
     printf("    eg: to run just the utility tests type: cintltest /tsutil) \n");
 }