John Pennington Thomasson (19 May 1841, in Bolton – 16 May 1904, in Heaton, Greater Manchester) was an English cotton spinner and Liberal Party politician. He was elected as a Member of Parliament (MP) for Bolton at the 1880 general election along with John Kynaston Cross in the double member constituency, signifying a great victory as two liberals were elected for the first time since 1852. He served for 5 years, when he lost his seat owing to the Home Rule split. He became a Liberal Unionist, although he returned to the Liberal fold eventually.