Timothy "Tim" Donaghy (pronounced /ˈdɒnəɡi/) (born January 7, 1967) is a former professional basketball referee who worked in the National Basketball Association (NBA) for 13 seasons, from 1994 to 2007. During his career in the NBA, Donaghy officiated in 772 regular-season games and 20 playoff games. Donaghy resigned from the league on July 9, 2007 before reports of an investigation by the Federal Bureau of Investigation (FBI) for allegations that he bet on games that he officiated during his last two seasons and that he made calls affecting the point spread in those games. On August 15, 2007, Donaghy pleaded guilty to two federal charges related to the investigation. However, he could face more charges at the state level if it is determined that he deliberately miscalled individual games. Donaghy was sentenced to 15 months in federal prison on July 29, 2008. He served 11 months in a federal prison camp in Pensacola, Florida, and will spend the remainder of his sentence in a halfway house.

Born in Havertown, Pennsylvania, Donaghy attended Cardinal O'Hara High School in Springfield, Pennsylvania along with three other NBA referees Joe Crawford, Mike Callahan, and Ed Malloy. Following high school, Donaghy attended and graduated from Villanova University with a degree in sales and marketing in 1989. While at Villanova, he played on the school's baseball team. According to the National Basketball Referee's Association, Donaghy participated and earned All-Catholic and All-Delaware County honors in baseball and All-Delaware County honors in basketball during high school, but then–Villanova baseball coach George Bennett contends that Donaghy did not play on the varsity team and that no records indicate that he was selected to the All-Catholic team in baseball or named to the All-Delaware County basketball team. Donaghy was married to his wife Kimberly, with whom he had four daughters, for 12 years before they divorced. One of Donaghy's favorite hobbies is golf.

Before officiating in the NBA, Donaghy spent five years working Pennsylvania high school games, seven seasons in the Continental Basketball Association (CBA), and was the head official for the 1993 CBA All-Star Game. The following year, he joined the NBA, where he worked for 13 years, officiating in 772 regular-season games and 20 playoff games. Donaghy was a participant in the NBA's Read to Achieve program, for which he participated in an event at the Universal Charter school during the 2002 NBA Finals. His uniform number was 21.