To provide an optical film having a low-refractive index layer excellent in low reflectivity, film strength, mass productivity, or the like, and a polarizing plate and an image display device which are low in reflectivity, can minimize projection of external light and make a reflected image less visible, and have superior visibility by being provided with the optical film.

The optical film includes at least the single low-refractive index layer on a transparent support, the low-refractive index layer being obtained by curing a composition, containing (A) at least one type among a hydrolysate and/or a condensation reaction product of organosilane and (B) a polyrotaxane compound.