A storage accessory for placement under a vehicle seat. The storage accessory comprises a first storage compartment, a second storage compartment, and a tray assembly for supporting the first and second storage compartments. At least one of the first and second storage compartments is removable from the tray assembly to serve as a stand-alone storage box when removed from the vehicle. The at least one removable storage compartment includes a lock handle that permits the at least one removable storage compartment to be releasably and securely attached to the tray assembly.