diff --git a/connect.c b/connect.c
index 574f42fa47..11fa151eb3 100644
--- a/connect.c
+++ b/connect.c
@@ -596,14 +596,17 @@ struct child_process *git_connect(int fd[2], const char *url_orig,
 		die("command line too long");
 
 	conn->in = conn->out = -1;
+	/* be sure to increase this size if you add more args */
 	conn->argv = arg = xcalloc(6, sizeof(*arg));
 	if (protocol == PROTO_SSH) {
 		const char *ssh = getenv("GIT_SSH");
+		int putty = ssh && strstr(ssh, "plink");
 		if (!ssh) ssh = "ssh";
 
 		*arg++ = ssh;
 		if (port) {
-			*arg++ = "-p";
+			/* P is for PuTTY, p is for OpenSSH */
+			*arg++ = putty ? "-P" : "-p";
 			*arg++ = port;
 		}
 		*arg++ = host;