William Brett 1st Viscount Esher
 William Baliol Brett 1st Viscount Esher PC QC (13 August 1817 – 24 May 1899) known as Sir William Brett between 1868 and 1883 was a British lawyer judge and Conservative politician. He was briefly Solicitor-General under Benjamin Disraeli and then served as a justice of the Court of Common Pleas between 1868 and 1876 as a Lord Justice of Appeal between 1876 and 1883 and as Master of the Rolls.