The 1040s was a decade of the Julian Calendar which began on January 1, 1040, and ended on December 31, 1049.
Significant people
- King Macbeth of Scotland (d. 1057)
- Godwin, Earl of Wessex (d. 1053)
- El Cid (b. 1040)
- Yaroslav I the Wise
- Al-Qa'im (caliph of Baghdad)