Sir Thomas Barrett-Lennard, 1st Baronet FSA, DL (6 January 1761 – 25 June 1857) was a British politician and baronet. He was the illegitimate son of the and Elizabeth FitzThomas. Barrett-Lennard was educated at Downing College, Cambridge. He entered the British House of Commons for Essex South in 1832 and was a Member of Parliament (MP) until 1835. Barrett-Lennard was a Deputy Lieutenant of Essex, and a Fellow of the Society of Antiquaries of London. On 30 June 1801, he was created a baronet, of Belhus, in the County of Essex.