John Brown Watt (16 May 1826 – 28 September 1897) was a Scottish-born Australian businessman, banker, and politician.

[1] Watt was appointed a member of the New South Wales Legislative Council in September 1861, and he resigned on leaving for England in March 1866.

In 1877, he presented the sum of £1000 to the University of Sydney to found an exhibition for students from primary schools.

[6] He was the Commissioner for New South Wales at the International Exhibitions of Philadelphia (1876), Paris (1878), Sydney (1879), Amsterdam (1883) and at Calcutta (1883–84).

Another son, Ernest Watt, became the father-in-law of Sir Laurence Whistler Street, when Street married Ernest's daughter Susan Gai Watt, who was the first female chair of the Eastern Sydney Health Service (now amalgamated with Illawarra).