David Martijn Westerholt (born 30 March 1979) is a Dutch musician and the founder, keyboardist and main songwriter of the symphonic metal band Delain.

He was previously a member of symphonic metal band Within Temptation, until he was diagnosed with infectious mononucleosis shortly after the release of Within Temptation's second full-length studio album, Mother Earth.

His brother Robert is the guitarist and founder of Within Temptation.

[1] He has lived in Zwolle,[2] since studying Communication at Windesheim College in 1998.

In September 2021, Westerholt formed a new symphonic project called Eye of Melian.