An objective lens for an endoscope includes, in order from an object side, a front lens group having negative refractive power as a whole, a brightness aperture stop, and a rear lens group having positive refractive power as a whole. The front lens group includes, in order from the object side, a first lens group having negative refractive power and that may include only a single lens; and a second lens group that may include only a single lens, with the second lens group having a lens surface closest to the image side that is of a concave form directed toward the image side, the second lens group having positive refractive power as a whole; and the following condition (1) is satisfied: |f0/f1|≦1.1  (1) where f0 is the composite focal length of the front lens group, and f1 is the focal length of the first lens group.