William Baliol Brett, 1st Viscount Esher, PC, 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. He was raised to the peerage as Baron Esher in 1885 and further honoured when he was made Viscount Esher on his retirement in 1897.

His Majesty's Solicitor General for England and Wales, known informally as the Solicitor General, is one of the law officers of the Crown in the government of the United Kingdom. They are the deputy of the Attorney General, whose duty is to advise the Crown and Cabinet on the law. They can exercise the powers of the Attorney General in the Attorney General's absence. Despite the title, the position is usually held by a barrister as opposed to a solicitor.