William Owen Stanley (13 November 1802-24 February 1884) was the Whig and Liberal Party MP for Anglesey from 1837 to 1847, for City of Chester from 1850 to 1857, and for Beaumaris from 1857 to 1874. The son of John Stanley, 1st Baron Stanley of Alderley and the twin of Edward Stanley, 2nd Baron Stanley of Alderley, he worked as a solicitor and served in the British Army as well as being a politician and an antiquarian.