An imaging lens may include a first lens L1 having negative power, a second lens L2 having negative power, a third lens L3 having positive power, a fourth lens L4 having negative power, and a fifth lens L5 having positive power, arranged in order from the object side. At least one of the third lens L3 and the fifth lens L5 may be formed of glass having a negative temperature coefficient of refractive index. A focal length of an entire system of the imaging lens is represented by f, the temperature coefficient of refractive index of the at least one of the third lens and the fifth lens formed of glass having a negative temperature coefficient of refractive index is represented by dn/dt, and the following conditions may be satisfied: dn/dt