The Academy Award for Best Supporting Actor is an award presented annually by the Academy of Motion Picture Arts and Sciences (AMPAS). It has been awarded since the 9th Academy Awards to an actor who has delivered an outstanding performance in a supporting role in a film released that year. The award is traditionally presented by the previous year's Best Supporting Actress winner. In lieu of the traditional Oscar statuette, supporting acting recipients were given plaques up until the 16th Academy Awards,^[1] when statuettes were awarded to each category instead.^[2]

The Best Supporting Actor award has been presented a total of 88 times, to 79 actors. The first winner was Walter Brennan for his role in Come and Get It. The most recent winner is Robert Downey Jr. for Oppenheimer.^[3] The record for most wins is three, held by Brennan–who won every other year within a succession of the first five years. Seven other actors have won twice. Brennan is also tied for receiving the most nominations in the category (with four altogether) along with Jeff Bridges, Robert Duvall, Arthur Kennedy, Jack Nicholson, Al Pacino, Claude Rains, and Mark Ruffalo.

Nominees are currently determined by single transferable vote within the actors branch of AMPAS; winners are selected by a plurality vote from the entire eligible voting members of the Academy.^[4]

In the first three years of the awards, actors and actresses were nominated as the best individuals in their categories, along with all qualifying cumulative work.^[5] The current system, in which an actor is nominated for a specific performance in a single film, was introduced for the 4th Academy Awards, in the lead acting categories.^[5] Simultaneously, along with the introduction of the supporting acting categories, all four acting categories were limited to a maximum five nominations per year.^[5]

In the following table, the years are listed as per Academy convention, and generally correspond to the year of film release in Los Angeles County; the ceremonies are always held the following year.^[6] For the first five ceremonies, the eligibility period spanned twelve months, from August 1 to July 31.^[7] For the 6th ceremony held in 1934, the eligibility period lasted from August 1, 1932, to December 31, 1933.^[7] Since the 7th ceremony held in 1935, the period of eligibility became the full previous calendar year from January 1 to December 31.^[7]

The following individuals received two or more Best Supporting Actor awards:

The following individuals received three or more Best Supporting Actor nominations:

There have been 22 instances in which films have produced more than one nominee within this category. All resulted in two nominations, with the exceptions of On the Waterfront (1954); The Godfather (1972); and The Godfather Part II (1974), which each obtained three.

Winners are in bold.

• Mr. Smith Goes to Washington (1939) -- Harry Carey Sr. and Claude Rains
• Quo Vadis (1951) -- Leo Genn and Peter Ustinov
• Shane (1953) -- Brandon deWilde and Jack Palance
• On the Waterfront (1954) -- Lee J. Cobb, Karl Malden, and Rod Steiger
• Peyton Place (1957) -- Arthur Kennedy and Russ Tamblyn
• Anatomy of a Murder (1959)-- Arthur O'Connell and George C. Scott
• The Hustler (1961) -- Jackie Gleason and George C. Scott
• Bonnie and Clyde (1967) -- Gene Hackman and Michael J. Pollard
• The Last Picture Show (1971) -- Jeff Bridges and Ben Johnson
• The Godfather (1972) -- James Caan, Robert Duvall, and Al Pacino
• The Godfather Part II (1974) -- Robert De Niro, Michael V. Gazzo, and Lee Strasberg
• Rocky (1976) -- Burgess Meredith and Burt Young
• Julia (1977) -- Jason Robards and Maximilian Schell
• Ordinary People (1980) -- Judd Hirsch and Timothy Hutton
• Terms of Endearment (1983) -- John Lithgow and Jack Nicholson
• Platoon (1986) -- Tom Berenger and Willem Dafoe
• Bugsy (1991) -- Harvey Keitel and Ben Kingsley
• Three Billboards Outside Ebbing, Missouri (2017) -- Woody Harrelson and Sam Rockwell
• The Irishman (2019) -- Al Pacino and Joe Pesci
• Judas and the Black Messiah (2020)^{[lower-alpha 4]} -- Daniel Kaluuya and LaKeith Stanfield
• The Power of the Dog (2021) -- Jesse Plemons and Kodi Smit-McPhee
• The Banshees of Inisherin (2022) -- Brendan Gleeson and Barry Keoghan

• All Academy Award acting nominees
• List of awards for supporting actor
• Golden Globe Award for Best Supporting Actor – Motion Picture
• Screen Actors Guild Award for Outstanding Performance by a Male Actor in a Supporting Role
• BAFTA Award for Best Actor in a Supporting Role
• Satellite Award for Best Supporting Actor – Motion Picture
• Academy Award for Best Supporting Actress