John William Woolf (November 27, 1869 – February 22, 1950) was an American-born Canadian politician who served in the Legislative Assembly of the Northwest Territories and the Legislative Assembly of Alberta. Born in Utah to polygamous parents, he moved with them to Cardston, Alberta as a young man. There he became a prominent rancher, and was elected in the 1902 Northwest Territories election. When Alberta was created in 1905, he became a member of its first legislative assembly. He resigned that office in 1912 to return to the United States; his son believed that this was because he had taken a second wife and feared prosecution under Canadian polygamy laws. Back in Utah, he pursued a number of business ventures with his son. He died in 1950.