A lens assembly may include: a first lens having positive refractive power and including a convex subject side surface; a second lens; a third lens having negative refractive power and including a subject side surface being convex toward an image secsor side in a center portion thereof, through which an optical axis passes; a fourth lens having positive or negative refractive power; and a fifth lens having positive or negative refractive power. The first lens, the second lens, the third lens, the fourth lens, and the fifth lens may be sequentially arranged from a subject to an image sensor along the optical axis. The lens assembly may satisfy a condition defined by 0.6