Sir Robert Gilmour Colquhoun, KCB (1803–1870) was a British diplomat.
He was educated at Pembroke College, Oxford. He was appointed Consul in Bucharest, Romania on 18 January 1835, Consul-General on 15 December 1837, and Agent and Consul-General on 18 November 1851. He received the Order of the Nichan Iftikhar. He was employed in Bosnia in 1854.
He was appointed Agent and Consul-General in Egypt on 14 January 1859. He served there until he retired in 1865 with the confidence and respect of the British government, and the rank of Knight-Commander of the Bath.