Sir William Salusbury-Trelawny, 8th Baronet  Sir William Lewis Salusbury-Trelawny, 8th Baronet (4 July 1781 – 15 November 1856), was a British politician. Born William Trelawny, he assumed in 1802 the additional surname of Salusbury. He served as High Sheriff of Cornwall in 1811  and later sat as Member of Parliament for Cornwall East from 1832 to 1837. He served as Lord-Lieutenant of Cornwall from 1839 to 1856. Salusbury-Trelawny died in November 1856, aged 69. He had married in 1807 Patience Christian Carpenter; they had several children. He was succeeded by his second son John as his eldest son Owen had died at a young age in 1830.