| Honorific-Prefix: | The Right Honourable |
| Thibaudeau Rinfret | |
| Order: | 9th |
| Office: | Chief Justice of Canada |
| Predecessor: | Lyman Poore Duff |
| Successor: | Patrick Kerwin |
| Term Start: | January 8, 1944 |
| Term End: | June 22, 1954 |
| Nominator: | William Lyon Mackenzie King |
| Office2: | Puisne Justice of the Supreme Court of Canada |
| Predecessor2: | Arthur Malouin |
| Successor2: | Roy Kellock |
| Term Start2: | October 1, 1924 |
| Term End2: | January 8, 1944 |
| Nominator2: | William Lyon Mackenzie King |
| Birth Date: | 22 June 1879 |
| Birth Place: | Montreal, Quebec |
| Nationality: | Canadian |
| Relations: | Fernand Rinfret, brother Charles Rinfret, brother |
| Alma Mater: | Université Laval à Montréal, Faculté de droit and McGill University |
| Occupation: | Lawyer, jurist |
Thibaudeau Rinfret (June 22, 1879 - July 25, 1962) was a Canadian jurist and the ninth Chief Justice of Canada and Administrator of Canada in 1952.
Rinfret was born in Montreal in 1879, the son of François-Olivier Rinfret and Albina Pominville.[1] He was the brother of Fernand Rinfret, Liberal politician who became Mayor of Montreal, and brother of Charles Rinfret, a prominent Montreal businessman.[2]
Rinfret studied law at the Université Laval à Montréal, Faculté de droit and McGill University and was called to the Bar of Quebec in 1901. He was appointed to the Quebec Superior Court in 1922 and to the Supreme Court of Canada in 1924.
Rinfret became Chief Justice on January 8, 1944, and served until his retirement on June 22, 1954. During his term as Chief Justice, Canada ended appeals to the Judicial Committee of the Privy Council making the Supreme Court of Canada the final court of appeal in Canadian jurisprudence.[3]
Rinfret was Administrator of the Government in 1952 after the departure of Harold Alexander, 1st Earl Alexander of Tunis, and until Vincent Massey could officially be sworn in as Governor General of Canada. During this time he proclaimed Elizabeth II as Queen of Canada, following the death of King George VI.
His son was the Quebec politician and judge Édouard Rinfret.