List of Famous people born in Ontario, Canada

Gloria Elizabeth Reuben is a Canadian actress, producer, and singer. She is known for her role as Jeanie Boulet on the medical drama ER, for which she was twice-nominated for an Emmy Award, and for portraying Elizabeth Keckley in the 2012 Academy Award–winning film Lincoln.

Louise Penny is a Canadian author of mystery novels set in the Canadian province of Quebec centred on the work of francophone Chief Inspector Armand Gamache of the Sûreté du Québec. Penny's first career was as a radio broadcaster for the Canadian Broadcasting Corporation (CBC). After she turned to writing, she won numerous awards for her work, including the Agatha Award for best mystery novel of the year five times, including four consecutive years (2007–2010), and the Anthony Award for best novel of the year five times, including four consecutive years (2010–2013). Her novels have been published in 23 languages.

Joseph John Valtellini is a Canadian retired Muay Thai kickboxer who competed in the super middleweight division. Nicknamed "Bazooka Joe", Valtellini is a strong and explosive fighter possessing considerable punching power and powerful low kicks. After winning provincial and national honours as an amateur, he turned professional in 2010 and went undefeated while finishing all of his opponents on the New York Muay Thai scene over the next two years before losing to Grégory Choplin in Lion Fight. He debuted with the Glory promotion in April 2013. He now works as a commentator for the promotion.

Owen Power is a Canadian collegiate ice hockey defenceman for the University of Michigan of the National Collegiate Athletic Association (NCAA) as a prospect of the Buffalo Sabres of the National Hockey League (NHL). He was drafted first overall by the Sabres in the 2021 NHL Entry Draft.

Paul Wilson Dewar was a Canadian educator and politician from Ottawa, Ontario. He was the New Democratic Party (NDP) Member of Parliament (MP) for the riding of Ottawa Centre.

Gordon Keith Brown was a Canadian politician who represented the Ontario riding of Leeds—Grenville—Thousand Islands and Rideau Lakes in the House of Commons of Canada as a member of the Conservative Party from 2004 until his death.

Alexander Chorostkowski, known as Alex Carson,, was a Canadian football player who played for the Ottawa Rough Riders. He won the Grey Cup with them in 1951.

Thomas Cavanagh is a Canadian actor. He is known for a variety of roles on American television, including starring roles in Ed (2000–2004), Love Monkey (2006) and Trust Me (2009), and recurring roles on Providence and Scrubs. Since 2014, he has portrayed Eobard Thawne / Reverse-Flash, and the various versions of Harrison Wells, on The CW television series The Flash; Cavanagh has also directed several episodes of The Flash.

Brandon Montour is a Canadian professional ice hockey defenceman for the Buffalo Sabres in the National Hockey League (NHL). Montour was selected by the Anaheim Ducks in the second round, 55th overall, of the 2014 NHL Entry Draft.

John Muckler was a professional hockey coach and executive, who last served as the general manager of the Ottawa Senators of the National Hockey League (NHL). Muckler had over 50 years of professional hockey experience as a part owner, general manager, director of player personnel, director of hockey operations, head coach, assistant coach and player. He had been a part of five Stanley Cup championships in various roles.