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. In an alternative arrangement, the fluid outlet is provided in an end wall of the reservoir and the fluid inlet is provided in a sidewall of the reservoir.