Abstract: A luminaire ballast mounting means for mounting ballast in a housing having a flat side wall includes a pair of linear rods that extend through a corresponding pair of openings arranged in a spaced relation along one side of the ballast. One pair of adjacent projected rod end sections is received within and in bearing engagement with a support member secured to the housing side wall and the other pair of projected rod end sections is engageable with a clamping means carried on the housing side wall and operable to move the other pair of rod end sections toward the side wall. When thus moved, the rods are flexed between the support member and clamping means to positions wherein the ballast is clamped against the housing side wall.