A retrofit LED lighting fixture, comprising: a luminaire housing having an opening, said luminaire housing having a top wall opposite said opening; said luminaire housing defining an internal cavity; said luminaire housing having a first side member positioned between said opening and said top wall, said first side member having a junction box aperture; a junction box containing a power supply, said junction box matingly received in said junction box aperture of said luminaire housing; said junction box having a face plate removably affixed to said junction box by at least one affixation mechanism; and characterised in that the retrofit LED lighting fixture further comprises: a light engine module removably retained within said internal cavity of said luminaire housing, said light engine module having at least one LED; a side wall; a light exit aperture substantially covered by a lens; a second top wall, a planar support member mounted to said second top wall; said at least one LED mounted on said planar support member, said planar support member positioned adjacent to said second top wall; said light engine module having at least one first clip extending into said luminaire housing; and at least one second clip attached to said luminaire housing, said at least one second clip frictionally engaging and separable from said at least one first clip such that a pulling force will separate said at least one first clip and said at least one second clip. a luminaire housing having an opening, said luminaire housing having a top wall opposite said opening; said luminaire housing defining an internal cavity; said luminaire housing having a first side member positioned between said opening and said top wall, said first side member having a junction box aperture; a junction box containing a power supply, said junction box matingly received in said junction box aperture of said luminaire housing; said junction box having a face plate removably affixed to said junction box by at least one affixation mechanism; and characterised in that the retrofit LED lighting fixture further comprises: a light engine module removably retained within said internal cavity of said luminaire housing, said light engine module having at least one LED; a side wall; a light exit aperture substantially covered by a lens; a second top wall, a planar support member mounted to said second top wall; said at least one LED mounted on said planar support member, said planar support member positioned adjacent to said second top wall; said light engine module having at least one first clip extending into said luminaire housing; and at least one second clip attached to said luminaire housing, said at least one second clip frictionally engaging and separable from said at least one first clip such that a pulling force will separate said at least one first clip and said at least one second clip. a light engine module removably retained within said internal cavity of said luminaire housing, said light engine module having at least one LED; a side wall; a light exit aperture substantially covered by a lens; a second top wall, a planar support member mounted to said second top wall; said at least one LED mounted on said planar support member, said planar support member positioned adjacent to said second top wall; said light engine module having at least one first clip extending into said luminaire housing; and at least one second clip attached to said luminaire housing, said at least one second clip frictionally engaging and separable from said at least one first clip such that a pulling force will separate said at least one first clip and said at least one second clip.