Thomas Bayley Potter DL, JP (29 November 1817 – 6 November 1898) was a British Liberal Party politician.
Born in Polefield, Lancashire, he was the second son of Sir Thomas Potter and his wife Esther Bayley, daughter of Thomas Bayley. Potter was educated at Rugby School under Dr. Arnold and then at University College, London. In 1863 he was the founder and president of the Union and Emancipation Society. In 1865, Potter entered the British House of Commons and sat as Member of Parliament (MP) for Rochdale until 1895. He was a Justice of the Peace for Manchester and Lancashire, and for the latter also Deputy Lieutenant. In the House of Commons he was known as "Principles Potter".
He also established the Cobden Club and supported Italian Unity and was a personal friend of Garibaldi.
He married firstly Mary Ashton, daughter of Samuel Ashton at the Unitarian Chapel of Gee Cross on 5 February 1846. She died in 1885 and Potter married secondly Helena Hicks, daughter of John Hicks at St Paul's Church, Lambeth, Surrey on 10 March 1887. Potter had four sons and a daughter by his first wife. He died, aged 80 in The Hurst, Sussex and was buried in Heyshott four days later.