An axle assembly is provided and includes an axle component, a pinion nut, and a retainer. The axle component has a recess that defines a wall portion. The pinion nut is received within the recess. The retainer is received within the recess and is disposed between the pinion nut and the wall portion. The retainer is movable between a compressed state and a first expanded state, whereby the compressed state permits movement of the retainer relative to the pinion nut and the first expanded state engages the pinion nut and the wall portion to restrict movement of the retainer relative to the pinion nut and the wall portion.