Treaty No. 9 is a numbered treaty first signed in 1905–1906 between Anishinaabe and Omushkegowuk Cree communities and the Canadian Crown, which includes both the government of Canada and the government of the province of Ontario. It is commonly known as the "James Bay Treaty," since the eastern edge of the treaty territory is the shore of James Bay in Northern Ontario.

The Numbered Treaties are a series of eleven treaties signed between the First Nations, one of three groups of Indigenous Peoples in Canada, and the reigning monarch of Canada from 1871 to 1921. These agreements were created to allow the Government of Canada to pursue settlement and resource extraction in the affected regions, which include modern-day Alberta, British Columbia, Manitoba, Ontario, Saskatchewan, and the Northwest Territories. These treaties expanded the Dominion of Canada with large tracts of land in exchange for promises made to the indigenous people of the area. These terms were dependent on individual negotiations and so specific terms differed with each treaty.