Thomas Grimston Estcourt (1775–1853), of New Park, near Devizes, Wiltshire, later known as Thomas Grimston Bucknall Estcourt, was an English politician. He was the eldest son of Thomas Estcourt, Member of the Parliament of Great Britain (MP) for Cricklade. He was MP for Devizes23 January 1805 – February 1826 and for Oxford University 22 February 1826 – 1847.