| William Byron, Lord Byron | |
| Office: | Member of the House of Lords Lord Temporal |
| Term Start: | 4 October 1679 |
| Term End: | 13 November 1695 Hereditary peerage |
| Predecessor: | Richard Byron, 2nd Baron Byron |
| Successor: | William Byron, 4th Baron Byron |
| Noble Family: | Byron |
| Father: | Richard Byron, 2nd Baron Byron |
| Mother: | Elizabeth Rossell |
| Spouse: | Hon. Elizabeth Chaworth |
| Issue: | William Byron, 4th Baron Byron Hon. William Byron Hon. Richard Byron Hon. John Byron Hon. Ernestus Byron |
| Birth Date: | 1636 |
| Death Date: | 13 November 1695 (aged 59) |
William Byron, 3rd Baron Byron (1636 – 13 November 1695) was an English nobleman, peer, politician, and a poet.
Byron was the son of Richard Byron, 2nd Baron Byron and Elizabeth Rossell. He succeeded to the title of 3rd Baron Byron in 1679 upon the death of his father.
Lord Byron died on 13 November 1695, and was succeeded by his fifth (but only surviving) son William Byron, 4th Baron Byron (born 1669/70).
Lord Byron married the Hon. Elizabeth Chaworth, daughter of John Chaworth, 2nd Viscount Chaworth of Armagh and Hon. Elizabeth Noel, in 1660. They had five sons, but the first four died in infancy:
Lord Byron married Elizabeth Stonhouse, daughter of Sir George Stonhouse, 3rd Bt. and Margaret Lovelace, on 25 June 1685.
A daughter (from which of the two marriages is unclear), Hon. Catherine Byron, died in 1746. She married Arthur Cole, 1st Baron Ranelagh; they had no children.