On 10 March 1758 Howe married Mary Hartop; they had three daughters. His titles of Viscount and Earl Howe therefore became extinct with a lack of a male heir. His eldest daughter Sophia Howe became Baroness Howe in her own right: she married twice, firstly to The Hon. Penn Assheton Curzon, son of Assheton Curzon, 1st Viscount Curzon, and his first wife Esther Hanmer, and secondly, in 1812, to Sir Jonathan Waller. She died on 3 December 1835 aged 73, and is buried in Holy Trinity Church, Penn, Buckinghamshire. Sophia's eldest surviving son, Richard, was created Earl Howe in 1821.
