Dalton James Patrick McGuinty, Jr., MPP (born July 19, 1955 in Ottawa, Ontario) is a Canadian lawyer and politician and, since October 23, 2003, Premier of Ontario. He is the twenty-fourth premier of Ontario, and the second Roman Catholic to hold this office.
McGuinty is generally regarded as holding moderate views on economic issues, with his first budget raising personal taxes and planning to eliminate the province's tax on the capital of corporations. He holds liberal views on social issues, supporting abortion rights and same-sex marriage. In early 2005, his government passed legislation confirming the legal status of same-sex marriage in Ontario.
McGuinty was born in Ottawa. His parents are politician and professor Dalton McGuinty Sr. and full-time nurse Elizabeth McGuinty. Being the son of a francophone mother and an anglophone father, McGuinty became bilingual. He grew up in an Irish Canadian Catholic family with nine brothers and sisters, with younger brother David representing the riding of Ottawa South in the Canadian House of Commons since 2004.