In 1765 Ramsden married Sarah Dollond, daughter of John Dollond, the famous maker of high quality lenses and optical instruments. Ramsden received a share in Dollond's patent achromatic lens as dowry. Little is known of their life together but Sarah did not accompany him when he moved his workshop (and home). In 1773, Ramsden moved to 199 Piccadilly but Sarah and her son lived at Haymarket at a home belonging to her father's family. At the time of her death on 29 August 1796 she lived at Hercules Buildings, off Westminster Road, Lambeth. She was buried at St Mary's, Lambeth, on 1 September 1796. In his later years he lived above the workshop with a number of his apprentices. The Ramsdens had two sons and two daughters with only one, John, living past infancy. John later became a commander in the East India Company's navy.