Sir Joseph-Adolphe Chapleau, PC, KCMG (November 9, 1840 – June 13, 1898), born in Sainte-Thérèse, Quebec, was a French-Canadian lawyer and politician.
As a lawyer, he defended Ambroise-Dydime Lépine against the charge of murdering Thomas Scott during the Red River Rebellion of 1869 – 1870.
He served as the fifth Premier of the Canadian province of Quebec, federal Cabinet minister, and the seventh Lieutenant Governor of Quebec.
After the 1878 Quebec election, he was the Leader of the Opposition. He became premier in 1879 after the fall of the minority government of Henri-Gustave Joly de Lotbinière. He won the 1881 election, but resigned on July 29, 1882 to seek election to the federal House of Commons.
He won a by-election held on August 16, 1882.
Chapleau planned to quit politics in 1885 when Louis Riel was sentenced to be hanged but decided to stay, fearing it would only inflame the situation.
After Riel was hanged, he was attacked by Quebecers who accused him of the death of Riel along with John A. Macdonald.
He served as Minister of Justice under prime ministers John A. Macdonald and John Abbott, but declined to serve under John Thompson. He resigned in 1892, and was appointed Lieutenant Governor of Quebec from December 1892 until January 1898. He died in June of that same year in Montreal.
He won the 1881 election.
On 25 November 1874, he married Marie Louise, daughter of Lieutenant-colonel Charles King of Sherbrooke in the province of Quebec.