Battery-powered children's ride-on vehicles having battery retainer assemblies, and retainer assemblies for such vehicles. The battery retainer assembly includes a retaining member that is pivotally coupled relative to the vehicle's battery compartment. The retaining member is selectively pivoted between an open position, in which the retaining member permits the battery assembly to be inserted into or removed from the compartment, and a closed position, in which the retaining member obstructs removal of the battery assembly. In some embodiments, the retaining member is adapted to displace the battery assembly as the retaining member is pivoted to the open position. In some embodiments, the retaining member extends in the closed position across a proximal surface of the battery assembly. In some embodiments, the retaining member is adapted to automatically pivot to the closed position upon insertion of the battery assembly into the compartment and/or into engagement with the retaining member.