A lens module includes a first lens having a convex object-side surface and a convex image-side surface, a second lens having a concave object-side surface; a third lens having a meniscus shape; and a fourth lens having an inflection point formed on an image-side surface and a convex object-side surface. A distance from an image-side surface of the third lens to the object-side surface of the fourth lens may be less than 0.05. In an embodiment, r2, a radius of curvature of an image-side surface of the first lens, and, f, an overall focal length of an optical system including the first through fourth lenses may satisfy −0.94