Robin McLaurin Williams (July 21, 1951 – August 11, 2014) was an American actor and comedian. Known for his improvisational skills and the wide variety of characters he created spontaneously and portrayed in drama and comedy films, he is regarded as one of the greatest comedians of all time. Williams received numerous accolades including an Academy Award, two Primetime Emmy Awards, and six Golden Globe Awards, as well as five Grammy Awards and two Screen Actors Guild Awards. He was awarded the Cecil B. DeMille Award in 2005.

Born in Chicago, Williams began performing stand-up comedy in San Francisco and Los Angeles during the mid-1970s, and released several comedy albums including Reality ... What a Concept in 1980. He rose to fame playing the alien Mork in the ABC sitcom Mork & Mindy (1978–1982). Williams received his first leading film role in Popeye (1980). He won the Academy Award for Best Supporting Actor for Good Will Hunting (1997). His other Oscar-nominated roles were for Good Morning, Vietnam (1987), Dead Poets Society (1989), and The Fisher King (1991).

Williams starred in the critically acclaimed dramas The World According to Garp (1982), Moscow on the Hudson (1984), Awakenings (1990), Insomnia (2002), One Hour Photo (2002), and World's Greatest Dad (2009). He also starred in Toys (1992), The Birdcage (1996), and Patch Adams (1998), and family films such as Hook (1991), Mrs. Doubtfire (1993), Jumanji (1995), Jack (1996), Flubber (1997), RV (2006), and the Night at the Museum series (2006–2014). He provided voice work in the animated films Aladdin (1992), Robots (2005), Happy Feet (2006) and Happy Feet Two (2011).

In his final years, Williams struggled with severe depression before his death from suicide in 2014 at his Paradise Cay, California, home at age 63. According to his widow, Williams had been diagnosed with Parkinson's disease, and had been experiencing depression, anxiety, and increasing paranoia. His autopsy found "diffuse Lewy body disease", and Lewy body dementia professionals said his symptoms were consistent with dementia with Lewy bodies. In the weeks following his suicide, Williams was celebrated in a wave of tributes.

Robin McLaurin Williams was born at St. Luke's Hospital in Chicago, Illinois, on July 21, 1951. His father, Robert Fitzgerald Williams (1906–1987), was a senior executive in Ford's Lincoln-Mercury Division. His mother, Laurie McLaurin (1922–2001), was a former model from Jackson, Mississippi, whose great-grandfather was Mississippi senator and governor Anselm J. McLaurin. Williams had two older half-brothers: a paternal half-brother, Robert (also known as Todd), and a maternal half-brother, McLaurin. While his mother was a practitioner of Christian Science, Williams was raised in his father's Episcopal faith. During a television interview on Inside the Actors Studio in 2001, Williams credited his mother as an important early influence on his humor, and he tried to make her laugh to gain attention.

Williams attended public elementary school at Gorton Elementary School in Lake Forest and later Deer Path Junior High School. He described himself as a quiet child who did not overcome his shyness until becoming involved with his high school drama department, while friends recalled him as being very funny. In late 1963, when Williams was 12, his father was transferred to Detroit. The family lived in a 40-room farmhouse on 20 acres (8 ha) in suburban Bloomfield Hills, Michigan, where Williams attended the private all-boys Detroit Country Day School. He excelled academically, served as class president, and was on the school's wrestling team, but was also bullied for his weight and would play at home by himself.

With both parents working, Williams was partly raised by the family's maid, who was his main companion. When Williams was 16, his father took early retirement and the family moved to Tiburon, California. Following their move, Williams attended Redwood High School in nearby Larkspur. Williams described the school as Gestalt, he went on to join the drama club becoming involved in theater, which first helped foster his interest in arts and entertainment. At the time of his graduation in 1969, he was voted "Most Likely Not to Succeed" and "Funniest" by his classmates. After high school graduation, Williams enrolled at Claremont Men's College in Claremont, California, to study political science; he dropped out to pursue acting. Williams studied theater for three years at the College of Marin, a community college in Kentfield, California. According to the College of Marin's drama professor, James Dunn, the depth of the young actor's talent became evident when Williams was cast in the musical Oliver! as Fagin. He often improvised during his time in the drama program, leaving cast members in hysterics. Dunn called his wife after one late rehearsal to tell her Williams "was going to be something special".

In 1973, Williams attained a full scholarship to the Juilliard School (Group 6, 1973–1976) in New York City. He was one of 20 students accepted into the freshman class, and Williams and Christopher Reeve were the only two accepted by John Houseman for the school's Advanced Program that year. Williams's classmates included William Hurt and Mandy Patinkin. According to biographer Jean Dorsinville, Franklyn Seales and Williams were roommates at Juilliard. Reeve recalled his first impression of Williams when they were new students at Juilliard: "He wore tie-dyed shirts with tracksuit bottoms and talked a mile a minute. I'd never seen so much energy contained in one person. He was like an untied balloon that had been inflated and immediately released. I watched in awe as he virtually caromed off the walls of the classrooms and hallways. To say that he was 'on' would be a major understatement."