The Best Actor Award (French: Prix d'interprétation masculine) is an award presented at the Cannes Film Festival since 1946. It is given to an actor who has delivered an outstanding performance and chosen by the jury from the films in official competition slate at the festival.

At the 1st Cannes Film Festival held in 1946, Ray Milland was the first winner of this award for his performance in The Lost Weekend, and Kōji Yakusho is the most recent winner in this category for his role in Perfect Days at the 76th Cannes Film Festival in 2023.

The award was first presented in 1946. The prize was not awarded on five occasions (1947, 1953–54, 1956, and 1960). The festival was not held at all in 1948, 1950, and 2020. In 1968, no awards were given as the festival was called off mid-way due to the May 1968 events in France. On four occasions, the jury has awarded multiple men (more than 2) the prize for one film. The four films were A Big Family (1955), Compulsion (1959), Long Day's Journey into Night (1962), and Days of Glory (2006). Dean Stockwell, Jack Lemmon, and Marcello Mastroianni have won the most awards in this category, each winning twice. The award can be for lead or supporting roles, with the exception of the period from 1979 to 1981, and in 1991, when the festival used to award a separate "Best Supporting Actor" prize. The jury also, on occasion, cites actors with a special citation that is separate from the main award.

The following individuals have received multiple Best Actor awards:

The following individuals have also received Best Actor award(s) at Venice or Berlin Film Festival.