John Grundy, Sr. (c.1696 – 1748) was a teacher of mathematics, a land surveyor, and later a civil engineer. Grundy lived in Congerstone, Leicestershire, England for the first forty years of his life; he later moved to Spalding in Lincolnshire. He was one of the first engineers to apply mathematical principles to the problems of land drainage. His son, John Grundy Jr., was also a civil engineer.