The invention is an optical film at least containing cellulose acylate and a compound having a structure denoted by General Formula (I) described below, and a polarizing plate and a liquid crystal display device employing the optical film. R1 and R3 represent a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, a cycloalkenyl group, or an aryl group, and R5a and R5b represent an alkyl group, an alkenyl group, a cycloalkyl group, a cycloalkenyl group, an aryl group, or a heterocyclic group. R1, R3, R5a, and R5b may have a substituent group.