diff --git a/Modules/main.c b/Modules/main.c
index 427b19b61f1..0cab8251575 100644
--- a/Modules/main.c
+++ b/Modules/main.c
@@ -61,7 +61,7 @@ static int  orig_argc;
 
 /* Short usage message (with %s for argv0) */
 static char *usage_line =
-"usage: %s [-d] [-i] [-s] [-u] [-v] [-c cmd | file | -] [arg] ...\n";
+"usage: %s [-d] [-i] [-O] [-s] [-u] [-v] [-c cmd | file | -] [arg] ...\n";
 
 /* Long usage message, split into parts < 512 bytes */
 static char *usage_top = "\n\
@@ -69,6 +69,7 @@ Options and arguments (and corresponding environment variables):\n\
 -d     : debug output from parser (also PYTHONDEBUG=x)\n\
 -i     : inspect interactively after running script, (also PYTHONINSPECT=x)\n\
          and force prompts, even if stdin does not appear to be a terminal.\n\
+-O     : optimize generated bytecode (a tad).\n\
 -s     : suppress printing of top level expressions (also PYTHONSUPPRESS=x)\n\
 -u     : unbuffered stdout and stderr (also PYTHONUNBUFFERED=x)\n\
 -v     : verbose (trace import statements) (also PYTHONVERBOSE=x)\n\
@@ -118,7 +119,7 @@ main(argc, argv)
 	if ((p = getenv("PYTHONUNBUFFERED")) && *p != '\0')
 		unbuffered = 1;
 
-	while ((c = getopt(argc, argv, "c:disuv")) != EOF) {
+	while ((c = getopt(argc, argv, "c:diOsuv")) != EOF) {
 		if (c == 'c') {
 			/* -c is the last option; following arguments
 			   that look like options are left for the
@@ -143,6 +144,10 @@ main(argc, argv)
 			Py_InteractiveFlag++;
 			break;
 
+		case 'O':
+			Py_OptimizeFlag++;
+			break;
+
 		case 's':
 			Py_SuppressPrintingFlag++;
 			break;