A resilient gasket for a weatherproof electrical outlet provides seals between the outlet box and the cover plate, between the receptacle and the cover plate, and between the cover plate and cover flap or plug connected to the receptacle. The gasket is a planar member having a peripheral configuration corresponding to the peripheral configurations of a standard outlet box and cover plate therefor and is received between the cover plate and receptacle and between the cover plate and outlet box. At least one aperture extends through the gasket and has transverse dimensions, in a relaxed condition of the gasket, less than the similar dimensions of projections on standard electrical receptacles. Upon assembly of the gasket within the electrical outlet, the portions of the gasket adjacent the aperture are stretched and deformed out of the plane of the gasket to provide a peripheral lip which extends through the cover plate opening, surrounds the receptacle projection, and contacts the cover flap in its closed position or the plug connected to the receptacle. In this manner, a single, unitary and continuous gasket is provided for the electrical outlet.