Abstract: A lap trim system and method is disclosed. In a particular embodiment, the system includes a pair of flanges joined along a longitudinal edge and extending generally at a right angle to each other and adapted to cover a corner formed by a plurality of pieces of overlapping siding. In addition, the system includes a rear surface along a free edge of each flange having at least one shoulder protruding from the rear surface of each flange in profile, where the at least one shoulder of each flange is adapted to fit along a lower edge of at least one piece of the plurality of pieces of overlapping siding.