Lionel Groulx (French: [ɡʁu]; 13 January 1878 – 23 May 1967) was a Canadian Roman Catholic priest, historian, professor, public intellectual and Quebec nationalist.

He believed the powers of the provincial government of Quebec could and should be used, within Confederation, to better the lot of the French Canadian nation, economically, socially, culturally and linguistically.

He would not sign, but finally agreed to a condition that he would limit himself to historical studies; he resigned from the editorship of L'action canadienne-française soon after, and the magazine ceased publication at the end of the year.

[7] He also developed a Quebec history curriculum that glorified French colonization in Canada, the difficulties imposed upon the Canadiens by the conquest of New France, and how these were countered by lengthy political struggles for democratic rights.

He bore particular affection for the undertaking of Robert Baldwin and Louis-Hippolyte Lafontaine, that in 1849 successfully restored the rights of the French language along with the obtention of responsible government, thus thwarting the assimilation plans of Lord Durham's policy of a union between the colonies of Upper and Lower Canada.

During the Second World War Groulx, like many Canadien nationalists, spoke in favour of the Vichy regime of Philippe Pétain, although public statements to this effect remained rare.

[9] Groulx and other intellectuals settled into a partial alliance with Liberal Party of Quebec leader Adelard Godbout, who served as Premier from 1939 to 1944.

Groulx founded the Institut d'histoire d'Amérique française in 1946, an institute located in Montreal devoted to the historical study of Quebec and of the French presence in the Americas and the publication of La revue d'histoire de l'Amérique française, still today arguably the main publication for professional historians in Quebec.

His main intellectual contribution was to create a rapprochement between nationalism and the Catholic religion, blunting the hostility between nationalists and the Church that had existed in the nineteenth century.

Through his writings and teaching at the university and his association with the intellectual elite of Quebec, he had a profound influence on many people (such as Michel Chartrand and Camille Laurin).

In June 2020, in the wake of global anti-racism and anti-police brutality protests, a petition was launched by Montréalers asking the city government to rename the Lionel-Groulx métro station after the African-Canadian jazz pianist Oscar Peterson.

[12] Accusations of anti-Semitism were made by Canadian author Mordecai Richler and French-Canadian historian Esther Delisle in the 1990s against several pre-World War II Quebec intellectuals, including Groulx.

[13] In 1933, writing under the pseudonym Jacques Brassier in the article "So That We May Live..." [Pour qu'on vive..."], published in the journal L'Action nationale [National Action], Groulx states his opposition to anti-Semitism.