| Honorific-Prefix: | The Right Honourable |
| The Lord Spencer of Wormleighton | |
| Baptised: | 4 January 1591 |
| Death Date: | 19 December 1636 (aged 45) |
| Spouse: | Lady Penelope Wriothesley |
| Children: | 6 (including Henry Spencer, 1st Earl of Sunderland and Robert Spencer, 1st Viscount Teviot) |
| Parents: | Robert Spencer, 1st Baron Spencer of Wormleighton Margaret Willoughby |
William Spencer, 2nd Baron Spencer of Wormleighton (1591 – 19 December 1636) was an English nobleman, politician, and peer from the Spencer family.
Spencer was the second son of Robert Spencer, 1st Baron Spencer of Wormleighton, and his wife, Margaret Willoughby, and was baptised on 4 January 1591 at Brington, Northamptonshire.[1] He matriculated at Magdalen College, Oxford with his elder brother John in October 1607.[2] In the autumn of 1610 he traveled to France with his brother.[3] On John's death at Blois in 1612, he became the heir to the barony. He became a Member of Parliament for Brackley in 1614, but left no trace in the records. As the member for Northamptonshire (1620–1622 & 1624–1627) he was an active participant in parliamentary sessions. From 6 May 1618 to 1621, Spencer held the office of Deputy Lieutenant of Northamptonshire. On 25 October 1627, he succeeded his father as 2nd Baron Spencer of Wormleighton.
Spencer married Lady Penelope Wriothesley, daughter of Henry Wriothesley, 3rd Earl of Southampton and Elizabeth Vernon in 1615. The couple had a number of children, including:
He died on 19 December 1636, aged 44.