David Justin Hayward (born 14 October 1946) is an English musician best known as the lead singer, songwriter and guitarist of the rock band the Moody Blues. Hayward became the group's principal lead guitarist and vocalist over the 1967–1974 period, and the most prolific songwriter and composer of several international hit singles for the band.

Hayward wrote singles for the Moody Blues including "Nights in White Satin", "Tuesday Afternoon", "Voices in the Sky", "Never Comes the Day", "Question", "The Story in Your Eyes", "Driftwood", "The Voice", "Blue World", "Your Wildest Dreams", "I Know You're Out There Somewhere" and "English Sunset"; in all, writing 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.