| William Byron, Lord Byron | |
| Office: | Member of the House of Lords Lord Temporal |
| Term Start: | 13 November 1695 |
| Term End: | 8 August 1736 Hereditary peerage |
| Predecessor: | William Byron, 3rd Baron Byron |
| Successor: | William Byron, 5th Baron Byron |
| Noble Family: | Byron |
| Birth Date: | 4 January 1669/70 |
| Death Date: | 8 August 1736 (aged 66) |
| Spouse: | Lady Mary Egerton Lady Frances Wilhelmina Bentinck Hon. Frances Berkeley |
| Issue: | Hon. George Byron Hon. William Byron Hon. William Henry Byron Hon. Isabella Byron, Countess of Carlisle William Byron, 5th Baron Byron Hon. John Byron Hon. Rev. Richard Byron Hon. George Byron |
| Father: | William Byron, 3rd Baron Byron |
| Mother: | Hon. Elizabeth Chaworth |
| Birth Place: | Newstead, Nottinghamshire |
| Death Place: | Newstead, Nottinghamshire |
William Byron, 4th Baron Byron (4 January 1669/70 - 8 August 1736) was an English nobleman, politician, peer, and Gentleman of the Bedchamber to Prince George of Denmark.
Byron was the only surviving son of William Byron, 3rd Baron Byron and Elizabeth Chaworth. He succeeded to the title of 4th Baron Byron in 1695 upon the death of his father.
Lord Byron firstly married Lady Mary Egerton, daughter of John Egerton, 3rd Earl of Bridgewater and Lady Jane Powlett, in 1702/3, but they had no children.
Secondly, he married Lady Frances Wilhelmina Bentinck, daughter of Hans William Bentinck, 1st Earl of Portland and Anne Villiers, in 1706. All four of their children died in childhood or infancy:
Frances Wilhelmina died on 31 March 1712.[1]
He married thirdly Frances Berkeley, daughter of William Berkeley, 4th Baron Berkeley of Stratton, and Frances Temple, in 1720. They had six children:
Lord Byron died at Newstead Abbey on 8 August 1736, and was succeeded by his fourth (but oldest surviving) son William Byron, 5th Baron Byron.
His widow Frances remarried Sir Thomas Hay, Bart., of Alderston[3] in 1741 and was buried on 21 September 1757 in Twickenham, Middlesex.[4]