Arthur Augustus Thomas (12 August 1862 - 18 June 1943) was a barrister and local politician.
Born in South Wales, Thomas was educated at St Paul's college, Cheltenham before moving to London to become a school teacher. In 1903 he was called to the bar at the Inner Temple. After practising on the South Wales Circuit, he returned to London where he became the standing counsel of the National Union of Teachers. He held the post of chairmen of governors of the Northern Polytechnic.
He was active in Liberal Party politics, and in 1904 was elected to the London County Council as a Progressive Party councillor representing Islington East. The county council had just taken over the management of schools from the abolished London School Board, and Thomas became a member of the first education committee. He lost his seat at the 1907 council elections when the Conservative-backed Municipal Reform Party took control of the county council. He regained the seat in 1910, standing down at the 1913 council elections.
He twice contested parliamentary elections as a Liberal candidate without success.
He had three daughters, one of whom, Dilys, married Frederick Dimbleby and was the mother of broadcasters and writers David and Jonathan Dimbleby.