Ultra vires (Latin for 'beyond powers') describes actions taken by an organization or government that exceed its legal authority. In municipal law, ultra vires actions are those municipalities lack statutory authority to take—bylaws, contracts, or decisions outside provincial grants of power can be challenged and invalidated. Courts can strike down ultra vires municipal actions. The ultra vires doctrine reflects municipalities' status as creatures of the province with only delegated powers. Historically, courts interpreted municipal powers narrowly, invalidating actions not explicitly authorized. Modern interpretation has become more generous, recognizing broad municipal powers and natural person powers granted in contemporary municipal legislation. However, municipalities must still act within their authorized scope, and ultra vires remains an available legal challenge.