A vehicle battery mounting structure includes: an energy absorption member that is provided at a vehicle body lower side of a floor panel, and that includes a first side wall portion sloping toward a vehicle body upper outside at a vehicle width direction inside of the energy absorption member, as viewed from a vehicle body longitudinal direction; and a battery frame made of resin that is disposed at the vehicle width direction inside of the first side wall portion, that supports a battery, and that includes a second side wall portion sloping toward the vehicle body upper outside at the vehicle width direction outside of the battery frame, as viewed from the vehicle body longitudinal direction, and facing the first side wall portion in the vehicle width direction.