A compact, light, and uniformly bright backlight assembly and a display device are disclosed. The backlight assembly includes a light source assembly, a substrate, and a transflective member. The light source assembly emits a first light with a first luminance uniformity. Then, the first light passes through the substrate above the light source assembly for producing enhanced luminance uniformity. Again, after the light is reflected from and/or transmitted through the transflective member, the luminance uniformity is even more enhanced. Therefore, the volume, weight, and luminance uniformity of the backlight assembly and the display device are enhanced.