Provided in this disclosure is a reversible power supply enclosure. A base component defines a body of the power supply enclosure. The base component includes a base surface and side surfaces formed along opposing edges of the base surface. An offset flange is formed along the base surface. A closed end component is connected to the base component and includes a second offset flange. The offset flanges displace the base component the predetermined distance from the mounting surface. A cover component includes a primary surface and a perpendicular secondary surface for enclosing the base component. A lip portion substantially surrounds the peripheries of the primary and secondary surfaces, thereby enabling the power supply enclosure to be reversibly mounted in either a vertical orientation or a horizontal orientation such that both orientations provide a moisture-resistant power supply enclosure.