(John) Thomas Baines (27 November 1820 – 8 May 1875) was an English artist and explorer of British colonial southern Africa and Australia. Born in King's Lynn, Norfolk, Baines was apprenticed to a coach painter at an early age. When he was 22 he left England for South Africa aboard the "Olivia" (captained by a family friend William Roome) and worked for a while in Cape Town as a scenic and portrait artist, and as official war artist during the so-called Eighth Frontier War for the British Army.
In 1855 Baines joined Augustus Gregory’s 1855–1857 Royal Geographical Society sponsored expedition across northern Australia as official artist and storekeeper. The expedition’s purpose was to explore the Victoria River district in the north-west and to evaluate the entire northern area of Australia in terms of its suitability for colonial settlement. His association with the North Australian Expedition was the highpoint of his career, and he was warmly commended for his contribution to it, to the extent that Mount Baines and the Baines River were named in his honour.
In 1858 Baines accompanied David Livingstone along the Zambezi, and was one of the first white men to view Victoria Falls. In 1869 Baines led one of the first gold prospecting expeditions to Mashonaland in what later became Rhodesia.
From 1861 to 1862 Baines and James Chapman undertook an expedition to South West Africa. Chapman’s Travels in the Interior of South Africa (1868) and Baines' Explorations in South-West Africa (1864), provide a rare account of different perspectives on the same trip. This was the first expedition during which extensive use was made of both photography and painting, and in addition both men kept journals in which, amongst other things, they commented on their own and each other’s practice.
In 1870 Baines was granted a concession to explore for gold between the Gweru and Hunyani rivers by Lobengula, leader of the Matabele nation. Thomas Baines died in Durban in 1875.
Baines is today best known for his detailed paintings and sketches which give a unique insight into colonial life in southern Africa and Australia. Many of his pictures are held by the National Library of Australia, National Archives of Zimbabwe, National Maritime Museum, Brenthurst Library and the Royal Geographical Society.