Sir John Charles Samuel Grenier was a Barrister and the 17th Attorney General of Ceylon. He was appointed on 30 September 1886, succeeding Francis Flemming, and held the office until his death in 1892. He was succeeded by Charles Layard.Grenier was born in Jaffna, Ceylon on 16 June 1840, son of Frederick Charles Grenier, Secretary of the District Court, Jaffna. He started his career as a sub-editor on the Ceylon Examiner and later first secretary of the Colombo Municipality.