A ladder stabilizer having a base plate that engages with a lower portion of the ladder and having a tire receiving portion at an end portion of the base plate. The weight of a vehicle tire on the tire receiving portion provides increased stability to the base plate of the ladder stabilizer. The tire receiving portion can be moved to either side of the base plate and can have a base plate-engaging mechanism on its bottom surface to couple with a mating surface of the base plate. The ladder can be retained by a leg retainer, rung retainer, or other retaining member that is coupled to a ladder retainer attachment portion of the base plate. Preferably, the ladder retainer mechanism includes some type of fastener or tensioning mechanism to secure the lower portion of the ladder to the base plate.
