Mario Casacci (Pontedera, 12 August 1925 – Rome, 8 July 1995) was an Italian screenwriter, known for having been, together with his colleague Alberto Ciambricco, the creator of the character of Lieutenant Sheridan (played on the small screen by the actor Ubaldo Lay) and the creator, in 1959, of the television program Giallo club (also with Ciambricco).