William Cawthra (29 October 1801 – 26 October 1880) was a philanthropist, business and civic leader and the eldest son of Joseph Cawthra. William, like his father, was associated with reformists and was considered anti-establishment, notwithstanding his wealth. William was elected to Toronto City Council as the Alderman for St. Lawrence Ward in 1836, a position his father held for one year until he was unseated in 1835 by conservative opposition.