O Óscar de Melhor Ator Secundário ou Coadjuvante (no original em inglês Academy Award for Best Supporting Actor) é um dos prêmios entregues anualmente pela Academia de Artes e Ciências Cinematográficas. Ele é entregue em honra a um ator que realizou uma interpretação extraordinária em um papel coadjuvante em cinema.
O primeiro vencedor da categoria foi Walter Brennan por seu papel de Swan Bostrom no filme Come and Get It, tendo recebido o prêmio durante a 9.ª Cerimônia Anual do Oscar em 1937. Inicialmente os vencedores de ambas as categorias de atores coadjuvantes recebiam uma placa em vez das tradicionais estatuetas. Entretanto, os vencedores passaram a receber a estatueta a partir da 16ª Cerimônia em 1944. Atualmente, os indicados são definidos por voto único transferível dentro do ramo dos atores da Academia; os vencedores por sua vez são escolhidos pela maioria relativa de todo os membros elegíveis da Academia.
Desde sua criação, o prêmio já foi entregue para 73 atores diferentes. Brennan é o recordista de maior número de vitórias com três. Brennan, Jeff Bridges, Robert Duvall, Arthur Kennedy, Jack Nicholson e Claude Rains são os recordistas de indicações com quatro cada. O vencedor mais recente é Kieran Culkin por seu papel como Benjamin "Benji" Kaplan no filme A Real Pain.
Vencedores e indicados + Legenda Vencedor Vencedor póstumo Indicação póstuma
Década de 1930 AnoVencedores e IndicadosFilmePersonagemRef 1937 Walter Brennan Come and Get It Swan Bostrom Mischa Auer My Man Godfrey Carlo Stuart Erwin Pigskin Parade Amos Dodd Basil Rathbone Romeu and Juliet Tebaldo Akim Tamiroff The General Died at Dawn General Yang 1938 Joseph Schildkraut The Life of Emile Zola Capitão Alfred Dreyfus || rowspan=5 align=center | |- | Ralph Bellamy || The Awful Truth || "Dan" Leeson |- | Thomas Mitchell || The Hurricane || Dr. Kersaint |- | H. B. Warner || Lost Horizon || Chang |- | Roland Young || Topper || Cosmo Topper |- | rowspan="5" style="text-align:center;"| 1939 ||style="background:#FAEB86" | Walter Brennan ||style="background:#FAEB86" | Kentucky ||style="background:#FAEB86" | Peter Goodwin' || rowspan=5 align=center | |- | John Garfield || Four Daughters || Mickey Borden |- | Gene Lockhart || Algiers || Regis |- | Robert Morley || Marie Antoinette || Rei Luís XVI da França |- | Basil Rathbone || If I Were King'' Rei Luís XI da França
Década de 1940 AnoVencedores e IndicadosFilmePersonagemRef 1940 Thomas Mitchell Stagecoach Dr. Josiah Boone Brian Aherne Juarez Imperador Maximiliano do México Brian Donlevy Beau Geste Sargento Markoff Harry Carey Mr. Smith Goes to Washington Presidente do Senado Claude Rains Senador Joseph Harrison Paine 1941 Walter Brennan The Westerner Juiz Roy Bean Albert Basserman Foreign Correspondent Van Meer William Gargan They Knew What They Wanted Joe Jack Oakie The Great Dictator Benzini Napaloni James Stephenson The Letter Howard Joyce 1942 Donald Crisp How Green Was My Valley Gwilym Morgan Walter Brennan Sergeant York Pastor Rosier Pile Charles Coburn The Devil and Miss Jones John P. Merrick James Gleason Here Comes Mr. Jordan Max Corkle Sydney Greenstreet The Maltese Falcon Kasper Gutman 1943 Van Heflin Johnny Eager Jeff Hartnett William Bendix Wake Island Soldado Aloysius K. Randall Walter Huston Yankee Doodle Dandy Jeremiah Cohan Frank Morgan Tortilla Flat O Pirata Henry Travers Mrs. Miniver James Ballard 1944 Charles Coburn The More the Merrier Benjamin Dingle Charles Bickford The Song of Bernadette Padre Peyramale J. Carrol Naish Sahara Giuseppe Claude Rains Casablanca Capitão Renault Akim Tamiroff For Whom the Bell Tolls Pablo 1945 Barry Fitzgerald Going My Way Padre Fitzgibbon Hume Cronyn The Seventh Cross Paul Roeder Claude Rains Mr. Skeffington Job Skeffington Clifton Webb Laura Waldo Lydecker Monty Woolley Since You Went Away Coronel William G. Smollett 1946 James Dunn A Tree Grows in Brooklyn Johnny Nolan Mikhail Chekhov Spellbound Dr. Alexander "Alex" Brulov John Dall The Corn Is Green Morgan Evans Robert Mitchum The Story of G.I. Joe Tenente-Capitão Bill Walker J. Carrol Naish A Medal for Benny Charley Martin 1947 Harold Russell The Best Years of Our Lives Hommer Parrish Charles Coburn The Green Years Alexander Gow William Demarest The Jolson Story Steve Martin Claude Rains Notorious Alexander Sebastian Clifton Webb The Razor's Edge Elliott Templeton 1948 Edmund Gwenn Miracle on 34th Street Kris Kringle Charles Bickford The Farmer's Daughter Joseph Clancy Thomas Gomez Ride the Pink Horse Pancho Robert Ryan Crossfire Montgomery Richard Widmark Kiss of Death Tommy Udo 1949 Walter Huston The Treasure of the Sierra Madre Howard Charles Bickford Johnny Belinda Black McDonald José Ferrer Joan of Arc Carlos, Delfim da França Oskar Homolka I Remember Mama Tio Chris Halverson Cecil Kellaway The Luck of the Irish Horace
Década de 1950 AnoVencedores e IndicadosFilmePersonagemRef 1950 Dean Jagger Twelve O'Clock High Major Harvey Stovall John Ireland All the King's Men Jack Burden Arthur Kennedy Champion Connie Kelly Ralph Richardson The Heiress Dr. Austin Sloper James Whitmore Battleground Sargento Kinnie 1951 George Sanders All About Eve Addison De Witt Jeff Chandler Broken Arrow Cochise Edmund Gwenn Mister 880 "Skipper" Miller Sam Jaffe The Asphalt Jungle Dr. Erwin Riedenschneider Erich von Stroheim Sunset Boulevard Max von Meyerling 1952 Karl Malden A Streetcar Named Desire Harold "Mitch" Mitchell Leo Genn Quo Vadis Petrônio Peter Ustinov Nero Kevin McCarthy Death of a Salesman Biff Loman Gig Young Come Fill the Cup Boyd Copeland 1953 Anthony Quinn Viva Zapata! Eufemio Zapata Richard Burton My Cousin Rachel Philip Ashley Arthur Hunnicutt The Big Sky Zeb Calloway / Narrador Victor McLaglen The Quiet Man "Red" Will Danaher Jack Palance Sudden Fear Lester Blaine 1954 Frank Sinatra From Here to Eternity Soldado Angelo Maggio Eddie Albert Roman Holiday Irving Radovich Brandon De Wilde Shane Joey Starrett Jack Palance Jack Wilson Robert Strauss Stalag 17 Sargento Stanislas "Animal" Kasava 1955 Edmond O'Brien The Barefoot Contessa Oscar Muldoon Lee J. Cobb On the Waterfront Johnny Friendly Karl Malden Padre Barry Rod Steiger Charles Malfoy Tom Tully The Caine Mutiny Comandante DeVriess 1956 Jack Lemmon Mister Roberts Alferes Frank Thurlowe Pulver Arthur Kennedy Trial Barney Castle Joe Mantell Marty Angie Sal Mineo Rebel Without a Cause John "Platão" Crowford Arthur O'Connell Picnic Howard Bevans 1957 Anthony Quinn Lust for Life Paul Gauguin Don Murray Bus Stop Beauregard "Bo" Decker Anthony Perkins Friendly Persuasion Josh Birdwell Mickey Rooney The Bold and the Brave Dooley Robert Stack Written on the Wind Kyle Hadley 1958 Red Buttons Sayonara Joe Kelly Vittorio De Sica A Farewell to Arms Major Alessandro Rinaldi Sessue Hayakawa The Bridge on the River Kwai Coronel Saito Arthur Kennedy Peyton Place Lucas Cross Russ Tamblyn Norman Page 1959 Burl Ives The Big Country Rufus Hannassey Theodore Bikel The Defiant Ones Xerife Max Muller Lee J. Cobb The Brothers Karamazov Fiódor Karamazov Arthur Kennedy Some Came Running Frank Hirsh Gig Young Teacher's Pet Dr. Hugo Pine
Década de 1960 AnoVencedores e IndicadosFilmePersonagemRef 1960 Hugh Griffith Ben-Hur Xeque Ilderim Arthur O'Connell Anatomy of a Murder Emmett McCarthy George C. Scott Proc. Estadual Assist. Gen. Claude Dancer Robert Vaughn The Young Philadelphians Chester A. "Chet" Gwynn Ed Wynn The Diary of Anne Frank Albert Dussell 1961 Peter Ustinov Spartacus Lêntulo Batiato Peter Falk Murder, Inc. Abe Reles Jack Kruschen The Apartment Dr. Dreyfuss Sal Mineo Exodus Dov Landau Chill Wills The Alamo O Apicultor 1962 George Chakiris West Side Story Bernardo Montgomery Clift Judgment at Nuremberg Rudolph PetersonPeter Falk Pocketful of Miracles Joy BoyJackie Gleason The Hustler Minnesota FatsGeorge C. Scott Bert Gordon 1963 Ed Begley Sweet Bird of Youth Tom Finley Victor Buono What Ever Happened to Baby Jane? Edwin Flagg Telly Savalas Birdman of Alcatraz Feto Gomez Omar Sharif Lawrence of Arabia Xarife Ali ibn el Kharish Terence Stamp Billy Budd Billy Budd 1964 Melvyn Douglas Hud Homer Bannon Nick Adams Twilight of Honor Ben Brown Bobby Darin Captain Newman, M.D. Cabo Jim Tompkins Hugh Griffith Tom Jones Squire Western John Huston The Cardinal Cardeal Glennon 1965 Peter Ustinov Topkapi Arthur Simon Simpson John Gielgud Becket Rei Luís VII da França Stanley Holloway My Fair Lady Alfred Doolittle Edmond O'Brien Seven Days in May Senador Raymond Clark Lee Tracy The Best Man Presidente Art Hockstader 1966 Martin Balsam A Thousand Clowns Arnold Burns Ian Bannen The Flight of the Phoenix Corvo Tom Courtenay Doctor Zhivago Pasha Antipov Michael Dunn Ship of Fools Carl Glocken Frank Finlay Othello Iago 1967 Walter Matthau The Fortune Cookie Willie Gingrich Mako The Sand Pebbles Po-han James Mason Georgy Girl James Leamington George Segal Who's Afraid of Virginia Woolf? Nick Robert Shaw A Man for All Seasons Rei Henrique VIII da Inglaterra 1968 George Kennedy Cool Hand Luke Dragline John Cassavetes The Dirty Dozen Victor P. Franko Gene Hackman Bonnie and Clyde Buck Barrow Michael J. Pollard C. W. Moss Cecil Kellaway Guess Who's Coming to Dinner Monsignor Mike Ryan 1969 Jack Albertson The Subject Was Roses John Cleary Seymour Cassel Faces Chet Daniel Massey Star! Noël Coward Jack Wild Oliver! O Trapaceio Astuto Gene Wilder The Producers Leopold "Leo" Bloom
Década de 1970 AnoVencedores e IndicadosFilmePersonagemRef 1970 Gig Young They Shoot Horses, Don't They? Rocky Rupert Crosse The Reivers Ned Elliott Gould Bob & Carol & Ted & Alice Ted Henderson Jack Nicholson Easy Rider George Hanson Anthony Quayle Anne of the Thousand Days Cardeal Tomás Wolsey 1971 John Mills Ryan's Daughter Michael Richard S. Castellano Lovers and Other Strangers Frank Vecchio Chefe Dan George Little Big Man Velho Lodge Skins Gene Hackman I Never Sang for My Father Gene Harrison John Marley Love Story Phil Cavalleri 1972 Ben Johnson The Last Picture Show Sam, o Leão Jeff Bridges The Last Picture Show Duane Jackson Leonard Frey Fiddler on the Roof Motel Kamzoil Richard Jaeckel Sometimes a Great Notion Joe Ben Stamper Roy Scheider The French Connection Detetive Buddy "Cloudy" Russo 1973 Joel Grey Cabaret Mestre de Cerimônias Eddie Albert The Heartbreak Kid Sr. Corcoran James Caan The Godfather Santino "Sonny" Corleone Robert Duvall Tom Hagen Al Pacino Michael Corleone 1974 John Houseman The Paper Chase Charles W. Kingsfield, Jr. Vincent Gardenia Bang the Drum Slowly Dutch Schnell Jack Gilford Save the Tiger Phil Greene Jason Miller The Exorcist Padre Damien Karras Randy Quaid The Last Detail Larry Meadows 1975 Robert De Niro The Godfather Part II Vito Corleone Fred Astaire The Towering Inferno Haire Claiborne Jeff Bridges Thunderbolt and Lightfoot Lightfoot Michael V. Gazzo The Godfather Part II Frank Pentangeli Lee Strasberg Hyman Roth 1976 George Burns The Sunshine Boys Al Lewis Brad Dourif One Flew Over the Cuckoo's Nest Billy Bibbit Burgess Meredith The Day of the Locust Harry Greener Chris Sarandon Dog Day Afternoon Leon Shermer Jack Warden Shampoo Lester Carp 1977 Jason Robards All the President's Men Ben Bradlee Ned Beatty Network Arthur Jansen Laurence Olivier Marathon Man Dr. Christian Szell Burgess Meredith Rocky Mickey Goldmill Burt Young Paulie Pennino 1978 Jason Robards Julia Dashiell Hammett Mikhail Baryshnikov The Turning Point Yuri Kopeikine Peter Firth Equus Alan Strang Alec Guinness Star Wars Obi-Wan Kenobi Maximilian Schell Julia Johann 1979 Christopher Walken The Deer Hunter Nikonar "Nick" Chevotarevich Bruce Dern Coming Home Capitão Bob Hyde Richard Farnsworth Comes a Horseman Dodger John Hurt Midnight Express Max Jack Warden Heaven Can Wait Max Corkle
Década de 1980