An extendable trailer assembly configured to be towed by a vehicle. The extendable trailer assembly includes a first compartment including a floor, a pair of opposing sidewalls, and a ceiling. The first compartment is configured to be coupled to a trailer hitch of the vehicle. The extendable trailer assembly also includes a second compartment including a floor, a pair of opposing sidewalls, and a ceiling. The extendable trailer assembly also includes a slide assembly slidably coupling the second compartment to the first compartment such that the second compartment is slidable relative to the first compartment between a fully extended position and a fully retracted position in which the first compartment is at least partially housed inside of the first compartment. The extendable trailer assembly is free of road-capable wheels for transport by the vehicle.