Abstract: A ladder safety device (100) is usable for holding and stabilizing a ladder in a safe and stable manner while being used, by way of securing a ladder relative to continuous horizontal guttering at the edge of a building. The device (100) locks to the gutter by way of locking jaws (130), (160) and is secured to the side rail of a ladder by way of an adjustable locking bar (140). Improvements to the initial design include an adjustable jaw (134) for clamping different thicknesses of gutter or other support material, selectable jaw strips (164a) to accommodate different types of gutters, and a ratcheting height adjustment carriage (150) for the locking bar (140) to accommodate different sizes of ladder rails.