Marie Thérèse Casgrain[1] CC OBE (née Forget; 10 July 1896 – 3 November 1981) was a French-Canadian feminist, reformer, politician and senator.

She was a leader in the fight for women's right to vote in the province of Quebec, as well as the first woman to lead a political party in Canada.

A strong federalist, one of her last political actions, at age 83, was to intervene on the "No" side in the 1980 Quebec sovereignty referendum.

Upon graduation, she hoped to further her studies at university, but her father opposed the idea, not seeing any utility in further education for women.

In his view, Thérèse should instead learn how to manage a household, a skill that would befit a future wife of her stature.

[5] In 1916, aged twenty, she married Pierre-François Casgrain, a wealthy Liberal politician with whom she raised four children.

[6] Thérèse's father, Sir Rodolphe, had represented the Charlevoix riding since the general election of 1904, holding it as a Conservative.

[8] Thérèse Casgrain accompanied her husband to Ottawa, the national capital, for the opening of the parliamentary session in the spring of 1918.

Although this was a clear attempt to gain votes in favour of the war effort, it was a significant milestone for women's suffrage in Canada.

Her tenacity, her political contacts through her husband (who eventually became Speaker of the House of Commons), her leadership and her ability to inspire, all helped her to achieve her goal of women's right to vote in Quebec.

She founded the Provincial Franchise Committee in 1921 and campaigned for women's rights, writing innumerable letters to influential people, making annual trips to the provincial capital at Quebec City, and broadcasts on radio, speaking for women's rights.

Following World War II, she left the Liberal Party and joined the social democratic Co-operative Commonwealth Federation (CCF).

[10] Prime Minister Pierre Trudeau appointed Casgrain to the Senate of Canada in 1970, where she sat as an independent for nine months before reaching the mandatory retirement age of 75.

It was during her period as a candidate with the CCF and the Parti social démocratique du Québec, that Casgrain acquired the reputation of a "pearl-necklace leftist."