A lens assembly includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens are arranged in order from an object side to an image side along an optical axis. The first lens has negative refractive power. The second lens has positive refractive power. The third lens has negative refractive power and includes a convex surface facing the image side. The fourth lens has positive refractive power and includes a concave surface facing the object side. The fifth lens has positive refractive power and includes a concave surface facing the image side.