A cutting guide for periacetabular osteotomy comprises at least one first main body (2) having a longitudinal opening (3) for the insertion of a cutting instrument (30), extending from a first end (2a) to a second end (2b) of the first main body (2) and at least two positioning and fixing arms (4a, 4b) extending away from the first main body (2) from opposite sides with respect to the longitudinal opening (3), in order to correctly position the first main body (2) on a bone and fix it thereto through respective fastening members (7).
