Backhouse married Anne the daughter of Brian Richards of Hartley Wespall in Hampshire, by whom he had two sons (who predeceased him) and a daughter, Flower. Backhouse also adopted Elias Ashmole, founder of the Ashmolean Museum, as his son, encouraging him in his studies. Flower Backhouse married, firstly, William Bishop of South Warnborough; secondly, her father's kinsman, Sir William Backhouse, Bart.; and, thirdly, Henry Hyde, 2nd Earl of Clarendon. [1]
Backhouse died at Swallowfield on 30th May 1662.[1]