The 1972–73 Segunda División was the 24th season of the Mexican Segunda División. The season started on 26 November 1972 and concluded on 5 July 1973. It was won by Ciudad Madero. As of this season, the promotion playoff was established between the Second and Third Division. The penultimate and antepenultimate classified of this category had to play a series against the second and third place of the Third Division.