'Parasite' has made history as the first foreign film to win a Best Picture Oscar, as well as the best international film and original screenplay categories.
The South Korean satire from Bong Joon-ho, who won Best Director, also won the Palme d'Or at Cannes. It is the first time a film has achieved both honours in 65 years, the last one being Delbert Mann's 1955 romantic drama 'Marty'.
Only 10 foreign-language films have previously been nominated for best picture.
The win was a surprise in an otherwise predictable ceremony, and may mark a shift in the academy's approach following debate over the awards' inclusiveness in recent years.