Sir Samuel Grimston, 3rd Baronet (1643-1700), was a politician.
Grimston was the second and only one of the six sons of Sir Harbottle Grimston, 2nd Baronet who survived him. He was born 7 January 1643. His mother was Sir Harbottle's first wife, Mary, daughter of Sir George Croke. He was elected member of parliament for St. Albans at a by-election in May 1668. He was not returned to the parliament of 1678, but was re-elected in 1679 and 1680. During the reign of James II he remained in private life, being, it is said, much disliked by the king, who expressly excepted him from pardon in the manifesto he issued when he contemplated landing in England (1692).
Grimston succeeded to his father's baronetcy in 1683, and was returned a member of the convention of 22 January 1689. From that time till May 1699 he sat continuously for his old borough. He married first Elizabeth, the eldest daughter of Heneage Finch, Earl of Nottingham, by whom he was father of a daughter, Elizabeth (d. 1694), who became first wife of William Savile, 2nd marquis of Halifax. Grimston's second wife was Lady Anne, sixth daughter of John Tufton, Earl of Thanet. By her he had a son and daughter, but both died young, and on his death, which occurred in October 1700, the Grimston baronetcy became extinct. Grimston left the family estates, which he had increased by the purchase of the manor of Windridge from Henry Osbaston, to his great-nephew, William Luckyn Grimston, second son of Sir William Luckyn of Messing Hall, Essex, who was son of Sir Capel Luckyn, by Mary, the eldest sister of Sir Samuel Grimston.
"Grimston, Samuel". Dictionary of National Biography. London: Smith, Elder & Co. 1885–1900.