Callum John Smith (born 23 April 1990) is a British professional boxer. He has held the WBA (Super) and Ring magazine super-middleweight titles since 2018, and won the World Boxing Super Series super-middleweight tournament in the same year. Previously at regional level he held the European and British super-middleweight titles between 2015 and 2017.

As of May 2020, he is ranked as the world's best active super-middleweight by the Transnational Boxing Rankings Board and ESPN, and second by BoxRec. He is the youngest of the Smith brothers—Paul, Stephen, and Liam—all of whom are professional boxers.