David Justin Hayward (born 14 October 1946) is an English musician. He was the guitarist and frontman of the rock band the Moody Blues from 1966 until its dissolution in 2018. He became the group's principal vocalist and its most prolific songwriter over the 1967–1974 period, and composed several international hit singles for the band.

Singles written by Hayward for the Moody Blues include "Nights in White Satin", "Tuesday Afternoon", "Question", "The Voice", "I Know You're Out There Somewhere" and "English Sunset"; he wrote 20 of the group's 27 post-1967 singles. He also has a solo career. His first album outside the Moody Blues, Blue Jays, a collaboration with John Lodge, reached the UK top five in 1975. The single "Blue Guitar", recorded with 10cc as the backing band, reached the UK top ten in 1975, and his 1978 recording of "Forever Autumn" from Jeff Wayne's Musical Version of The War of the Worlds reached the UK top five.

In 2018 Hayward was inducted into the Rock and Roll Hall of Fame as a member of the Moody Blues and in 2022 was appointed Officer of the Order of the British Empire (OBE) for services to the music industry.