diff --git a/src/themes/default/lv_theme_default.c b/src/themes/default/lv_theme_default.c
index fd1543544d..67ca6187f5 100644
--- a/src/themes/default/lv_theme_default.c
+++ b/src/themes/default/lv_theme_default.c
@@ -587,7 +587,7 @@ static void style_init(struct _my_theme_t * theme)
 #if LV_USE_MSGBOX
     style_init_reset(&theme->styles.msgbox_backdrop_bg);
     lv_style_set_bg_color(&theme->styles.msgbox_backdrop_bg, lv_palette_main(LV_PALETTE_GREY));
-    lv_style_set_bg_opa(&theme->styles.msgbox_backdrop_bg, LV_OPA_100);
+    lv_style_set_bg_opa(&theme->styles.msgbox_backdrop_bg, LV_OPA_50);
 #endif
 #if LV_USE_KEYBOARD
     style_init_reset(&theme->styles.keyboard_button_bg);
diff --git a/tests/ref_imgs/widgets/msgbox_ok_no_close_btn.png b/tests/ref_imgs/widgets/msgbox_ok_no_close_btn.png
index 83d5b39197..ddaf8be734 100644
Binary files a/tests/ref_imgs/widgets/msgbox_ok_no_close_btn.png and b/tests/ref_imgs/widgets/msgbox_ok_no_close_btn.png differ