diff --git a/config.def.h b/config.def.h
index e9ced7c..65f7259 100644
--- a/config.def.h
+++ b/config.def.h
@@ -3,6 +3,7 @@ static const int sloppyfocus        = 1;  /* focus follows mouse */
 static const unsigned int borderpx  = 1;  /* border pixel of windows */
 static const float rootcolor[]      = {0.3, 0.3, 0.3, 1.0};
 static const float bordercolor[]    = {0.5, 0.5, 0.5, 1.0};
+static const float focuscolor[]     = {1.0, 0.0, 0.0, 1.0};
 
 /* tagging */
 static const char *tags[] = { "1", "2", "3", "4", "5", "6", "7", "8", "9" };
diff --git a/dwl.c b/dwl.c
index 541f531..e56f7b9 100644
--- a/dwl.c
+++ b/dwl.c
@@ -1138,7 +1138,8 @@ render(struct wlr_surface *surface, int sx, int sy, void *data)
 void
 renderclients(Monitor *m, struct timespec *now)
 {
-	Client *c;
+	Client *c, *sel = selclient();
+	const float *color;
 	double ox, oy;
 	int i, w, h;
 	struct render_data rdata;
@@ -1164,9 +1165,15 @@ renderclients(Monitor *m, struct timespec *now)
 			{ox + c->bw + w, oy + c->bw, c->bw, h},     /* right */
 			{ox, oy + c->bw + h, w + 2 * c->bw, c->bw}, /* bottom */
 		};
+
+		if (c == sel)
+			color = focuscolor;
+		else
+			color = bordercolor;
+
 		for (i = 0; i < 4; i++) {
 			scalebox(&borders[i], m->wlr_output->scale);
-			wlr_render_rect(drw, &borders[i], bordercolor,
+			wlr_render_rect(drw, &borders[i], color,
 					m->wlr_output->transform_matrix);
 		}