Sir Thomas Rainsford Bavin, was an Australian lawyer and politician who served as Premier of New South Wales from 1927 to 1930. He was born in New Zealand and arrived in Australia at the age of 15, where he studied law and became a barrister. He served as personal secretary to Australia's first two prime ministers, Edmund Barton and Alfred Deakin. Bavin was elected to the New South Wales Legislative Assembly in 1917. He served two terms as Attorney General of New South Wales before leading the Nationalist Party to victory at the 1927 state election, in a coalition with the Country Party. His predecessor Jack Lang and the Australian Labor Party (ALP) defeated his government after a single term at the 1930 state election.

The premier of New South Wales is the head of government in the state of New South Wales, Australia. The Government of New South Wales follows the Westminster Parliamentary System, with a Parliament of New South Wales acting as the legislature. The premier is appointed by the Governor of New South Wales, and by modern convention holds office by their ability to command the support of a majority of members of the lower house of Parliament, the Legislative Assembly.