Sir John Douglas Hazen (June 5, 1860 - December 27, 1937) was a New Brunswick politician.

Hazen entered politics in 1885 serving as an alderman in Fredericton, New Brunswick before becoming mayor in 1888.

Hazen went on to sit in the Canadian House of Commons as a Conservative winning a seat in the 1891 Canadian election but lost his seat in the 1896 election that defeated the Conservatives and brought Wilfrid Laurier's Liberals to power.

He was elected to the provincial legislature in 1899 and became leader of the opposition. Hazen rebuilt the Conservative Party which had been out of power since 1883 leading the party to government in the 1908 election.

As Premier, Hazen combatted political corruption and fought attempts by the federal government to reduce the Maritime's representation in the federal House of Commons.

He left provincial politics in 1911 to become minister of marine and fisheries and minster of naval services in the government of Sir Robert Borden. During the First World War he served in the Imperial War Cabinet. Hazen left politics in October 1917 to become chief justice of New Brunswick.

He was interred in the Fernhill Cemetery in Saint John, New Brunswick.