diff --git a/slock.c b/slock.c
index d2f0886..61fe9ee 100644
--- a/slock.c
+++ b/slock.c
@@ -201,8 +201,13 @@ readpw(Display *dpy, struct xrandr *rr, struct lock **locks, int nscreens,
 			rre = (XRRScreenChangeNotifyEvent*)&ev;
 			for (screen = 0; screen < nscreens; screen++) {
 				if (locks[screen]->win == rre->window) {
-					XResizeWindow(dpy, locks[screen]->win,
-					              rre->width, rre->height);
+					if (rre->rotation == RR_Rotate_90 ||
+					    rre->rotation == RR_Rotate_270)
+						XResizeWindow(dpy, locks[screen]->win,
+						              rre->height, rre->width);
+					else
+						XResizeWindow(dpy, locks[screen]->win,
+						              rre->width, rre->height);
 					XClearWindow(dpy, locks[screen]->win);
 				}
 			}