James Grimston, 2nd Viscount Grimston (9 October 1711 – 15 December 1773) was a British peer and Member of Parliament.
Grimston was the son of William Grimston, 1st Viscount Grimston, and Jean Cooke. He was elected to the House of Commons for St Albans in 1754, a seat he held until 1761. In 1756 he succeeded his father in the viscountcy but as this was an Irish peerage it did not prohibit him from sitting in the House of Commons.
Lord Grimston married Mary Bucknall, daughter of William Bucknall, in 1746. He died in December 1773, aged 62, and was succeeded in his titles by his son James. Lady Grimston died in 1778.