Abstract: A ladder stabilizer for supporting a ladder against a structure and protecting surface features of the structure. Two stops 12 prevent the ladder from excessive lateral movement. A support bar 16 affixed to and extending between the stops provides support for the ladder. A mounting bracket 14 attached to each stop 12 is attached either directly to a structure surface, or to a U-shaped bracket 24 that fits around a rain gutter. Each U-shaped bracket fits over or under the rain gutter and is attached to a structure surface. In a second embodiment two support legs 118 bent at obtuse angles in two locations comprise an attachment portion 106 for attaching to the roof of a structure, a ramped portion 116 for extending beyond the roof eave, and a stop portion 114 for preventing excessive lateral movement of the ladder. A support bar 102 is affixed to and extends between the stop portions for supporting the ladder.