Abstract: A ladder safety apparatus (10, 60, 70, 80) stabilizes a ladder (36) residing against a structure (38) by effectively securing the upper end of the ladder (36) to the structure (38). The safety apparatus (10, 60, 70, 80) includes at least first and second side members (12, 13) that are interconnected at a transverse angle, preferably ninety degrees. An opening (22) is located in the second side member (13) for receiving and passing one of the ladder rails (39a, 39b) therethrough. The opening (22) has a first part (24) for passing the rail (39a, 39b) and a second part (26) that interconnects the first part (24) to a boundary edge (28) of the second side member (13). The second part (26) enables installation of the apparatus (10, 60, 70, 80). Optionally, one or more apertures (16) may be disposed in the first wall (12) for receiving and passing a gutter ferrule (52) or other pin-like member therethrough for further stabilization of the ladder (36).