An adapter allows direct connection of a handheld spray device to paint cans of varying dimensions. The adapter includes a cage for holding the paint can, a cap that connects the cage to the handheld spray device, and a gasket that seals the open upper end of the paint can to the cap. The adapter may also include a suction tube extension that is connectable between the pump inlet and the suction tube of the spray device. A can spacer insert is positionable in the cage to elevate paint cans of varying heights so that the upper ring of the paint can engages the gasket.