Gustave Lanctot, Canadian historian, author, and academic (d. 1975)
Gustave Lanctot , also spelled Gustave Lanctôt, (5 July 1883 – 2 February 1975) was a Canadian historian and archivist.

Born in Saint-Constant, Quebec, he studied law at Université de Montréal and was called to the Quebec Bar in 1907. A Rhodes Scholar, he studied political science and history from 1909 to 1911 while at Oxford University. He was also a member of the Oxford Canadians ice hockey team. In 1912, he joined the National Archives of Canada. During World War I, he served in the Canadian Expeditionary Force.

After the war, he received a PhD from the Sorbonne and later returned to the National Archives eventually becoming Dominion Archivist from 1937 to 1948. He also taught at the University of Ottawa.

A historian, he wrote many books including L'Administration de la Nouvelle-France (1929), Le Canada d'hier et d'aujourd'hui (1934), Montréal au temps de la Nouvelle-France, 1642-1760 (1942), Trois ans de guerre, 1939-1942 (1943), L'Oeuvre de la France en Amérique du Nord (1951), Histoire du Canada (winner of the 1963 Governor General's Award for French language non-fiction), Le Canada et la Révolution américaine (1965) et Montréal sous Maisonneuve, 1947-1965 (1966). He also was a historical advisor on eight Canadian films produced from 1961 to 1964.

He was made a Fellow of the Royal Society of Canada in 1926, was awarded the J. B. Tyrrell Historical Medal, and was its president from 1948 to 1949. On July 6, 1967, he was one of the first people to be made an Officer of the Order of Canada (then called a Service Medal). The citation read "Renowned historian whose "Histoire du Canada" marks the culmination of a life devoted to knowledge of Canada's past". He also was made a Knight of the Légion d'honneur.