Abstract: A ladder stabilizer adapted to attach to an upper end or lower end of an extension ladder includes a mounting plate connecting to a rung of the extension ladder by secure U-bolts, the mounting plate attached to a slide bar mounting bracket having a transverse channel with a tightening screw providing a force within the channel to lock and hold a pair of extendable service arms within the transverse channel to provide additional wide and secure lateral stabilization of the extension ladder either at the top of the extension ladder, where the extension ladder rests against a wall or roof, or at the bottom of the extension ladder where the extension ladder meets the ground.