Sir John Douglas Hazen, KCMG, PC (June 5, 1860 – December 27, 1937) was a politician in New Brunswick, Canada.

Known by his second name, Douglas, he entered politics in 1885 when he was elected as an alderman for Fredericton City Council.

He lost his seat in the 1896 election that defeated the Conservatives and brought Wilfrid Laurier's Liberals to power.

For his years of service to The Crown and to Canada, in 1918 Douglas Hazen was made a Knight Commander of the Order of St Michael and St George by King George V. Hazen died in 1937 at age seventy-seven and was interred in the Fernhill Cemetery in Saint John, New Brunswick.

Sir Douglas Hazen Park in Oromocto, New Brunswick and Sir Douglas Hazen Hall at the University of New Brunswick, Saint John are named in his honour.