Abstract: A starter strip for anchoring, to a wall, the bottom margins of the lowermost course of an array of horizontally elongated siding panels each secured to the wall along its top margin and each having an inwardly projecting, upwardly opening channel flange along its bottom margin. The starter strip includes a leg mountable on the wall, a locking flange arranged to be received within the channel flanges of the panels, and resilient biasing means such as a spring leg for acting against the inner surfaces of the panels to urge the bottom margins of the panels outwardly and thereby to hold the inner legs of their channel flanges against the inner edge of the locking flange.