A paint reservoir has a fluid outlet (115) connectable to a spray gun (101) and a fluid inlet (131) provided with a removable screw cap (132) whereby the fluid inlet (131) is directly accessible for introducing paint to the reservoir while attached to the spray gun (101). The fluid outlet (115) and fluid inlet (131) may both be provided in an end wall of the reservoir with outlet (115) located on the longitudinal axis of the reservoir or offset to allow the size of the fluid inlet (131) to be increased for easier filling of the reservoir. The outlet (115) can be aligned with the longitudinal axis of the reservoir or it can be inclined relative to the longitudinal axis to provide greater clearance for access to the fluid inlet (131) when the reservoir is attached to the spray gun (101).