A modular luminaire assembly comprising includes a mounting ring configured to be selectively coupled with a mounting surface, an inner housing defining a channel configured to receive the mounting ring, wherein the mounting ring is configured to be selectively coupled with the inner housing, a lighting assembly, one or more diffusers configured to direct light from the lighting assembly; and a retaining ring including a ring body defining an opening a plurality of flanges configured to snap engage with the inner housing, wherein the ring body is configured to at least partially support the one or more diffusers and the lighting assembly.