A pet booster seat for seating a pet on a vehicle seat in an elevated position is provided. The pet booster seat includes a base and four walls projecting upwardly from the base to define a pet seating portion. An L-shaped lap section and a supporting portion each extend downwardly from the base to define a groove for receiving a lap-style seatbelt. The pet booster seat preferably includes a removable cushion, a heating element for heating the removable cushion, a removable cover, and a strap for attachment to a pet's collar or harness.