The fourth Robertson ministry was the seventeenth ministry of the Colony of New South Wales, and was led by the Honourable John Robertson. It was the fourth of five occasions that Robertson led the Government. Robertson was elected in the first free elections for the New South Wales Legislative Assembly held in March 1856. The title of Premier was widely used to refer to the Leader of Government, but not enshrined in formal use until 1920. This ministry covers the period from 17 August 1877 until 17 December 1877, when Robertson was defeated by James Farnell at the December 1877 election.