The film from Hungary won the coveted award for Best Foreign Language Film, which was presented by Sofia Vergara and Byung Hun-Lee.
Director Lázló Nemes, whose been nominated nine times and took home his second win tonight, dedicated the award to his main actor and “the incredible cast who believed in this film when no one else did.”
“Even in the darkest hours of mankind there might be a voice within us that allows us to remain human – that’s the hope of this film,” he added.
The film also won for the same category at the Golden Globes in January.
Son of Saul, a Hungarian drama, was up against black-and-white Colombian film Embrace of the Serpent; Mustang, a French film about five young Turkish sisters; Theeb out of Jordan, and A War, a Danish film following the story of an Army commander in Afghanistan.
Notable past winners include Roberto Benigni’s Life Is Beautiful in 1997, Ang Lee’s Crouching Tiger, Hidden Dragon in 2000 and Michael Haneke’s Amour in 2012.
The 88th annual Awards, hosted by Chris Rock, are being presented live on ABC from the Dolby Theater in Hollywood, California.