An interlocking photovoltaic module mounting system that provides a one piece, integrated photovoltaic module frame portion that is directly mountable to a support structure and interlocks with separate adjoining photovoltaic module frame portions. The apparatus includes a frame member for enclosing the perimeter of a photovoltaic module, having an inside surface and outside surface, with the inside surface including a recess for capture of the panel. The frame member outside surface includes at least one interlocking means for affixation to the complementary outside surface of an adjacent frame-member. The frame member includes a height-adjustable foot portion for supporting the frame member on a roof, so that adjacent frame members may be interlocked to form an array, and the foot portion may be adjusted to level the formed array on the roof.