John Joseph Nicholson (born April 22, 1937) is an American actor and filmmaker who has performed for over sixty years. He is known for playing a wide range of starring or supporting roles, including satirical comedy, romance, and dark portrayals of anti-heroes and villainous characters. In many of his films, he has played the "eternal outsider, the sardonic drifter", someone who rebels against the social structure.

His most known and celebrated films include the road drama Easy Rider (1969); the dramas Five Easy Pieces (1970) and One Flew Over the Cuckoo's Nest (1975); the comedy-dramas The Last Detail (1973), Terms of Endearment (1983), As Good as It Gets (1997), About Schmidt(2002), and The Bucket List (2007); the neo-noir mystery Chinatown (1974); the horror film The Shining (1980); the biopic Reds (1981); the fantasy comedy The Witches of Eastwick (1987); the superhero film Batman (1989) as the Joker; the legal drama A Few Good Men (1992); the romantic horror film Wolf (1994); the science fiction comedy Mars Attacks! (1996); the comedy Anger Management (2003); the romantic comedy Something's Gotta Give (2003); and the crime drama The Departed (2006). Nicholson has not acted in a film since How Do You Know in 2010, but does not consider himself to be retired. He has also directed three films, including The Two Jakes (1990), the sequel to Chinatown.

Nicholson's 12 Academy Award nominations make him the most nominated male actor in the Academy's history. Nicholson has won the Academy Award for Best Actor twice – one for the drama One Flew Over the Cuckoo's Nest (1975), and the other for the romantic comedy As Good as It Gets (1997). He also won the Academy Award for Best Supporting Actor for the comedy-drama Terms of Endearment (1983). Nicholson is one of three male actors to win three Academy Awards. Nicholson is one of only two actors to be nominated for an Academy Award for acting in every decade from the 1960s to the 2000s; the other is Michael Caine. He has won six Golden Globe Awards, and received the Kennedy Center Honor in 2001. In 1994, at 57, he became one of the youngest actors to be awarded the American Film Institute's Life Achievement Award.

He has had a number of high-profile relationships, most notably with Anjelica Huston and Rebecca Broussard, and was married to Sandra Knightfrom 1962 until their divorce in 1968. Nicholson has five children – one with Knight, two with Broussard (including Lorraine Nicholson), and one each with Susan Anspach and Winnie Hollman.