William Philip Molyneux, 4th Earl of Sefton, KG (14 October 1835 – 27 June 1897) was a British peer.
Born Viscount Molyneux, he was the eldest son of Charles Molyneux, 3rd Earl of Sefton and his wife, Mary. He was educated at Eton College, Berks. In 1854, Molyneux became an ensign in the Grenadier Guards and inherited his father's earldom the following year. He was promoted to captain in 1857, retiring a year later, when he was appointed Lord Lieutenant of Lancashire.
On 18 July 1866, Lord Sefton married Hon. Cecil Emily Jolliffe (1838–1899), the fifth daughter of William Jolliffe, 1st Baron Hylton. They had five children:
Lord Sefton was appointed a Knight of the Garter in 1885. In 1886, he built Abbeystead House in the forest of Wyresdale, Lancashire as a 'private shooting lodge on a grand scale'. On his death in 1897, his titles passed to his eldest son, Charles.
The family seats were : Croxteth Hall, Lancs ; Abbeystead House, Lancs ; Sefton House, Belgravia Sq., London
| Honorary titles | ||
|---|---|---|
| Preceded by The Duke of Devonshire |
Lord Lieutenant of Lancashire 1858–1897 |
Succeeded by The Earl of Derby |
| Peerage of Ireland | ||
| Preceded by Charles Molyneux |
Earl of Sefton 1855–1897 |
Succeeded by Charles Molyneux |