Dirk Antoon Nico Marcellis (born 13 April 1988) is a Dutch former footballer who played as a centre back.

Born in Horst aan de Maas, Marcellis began his professional career at PSV.

On 30 July 2009, Marcellis scored a last-minute goal against Bulgarian side PFC Cherno More Varna to help his team to a 1–0 home win in a third qualifying round game of the UEFA Europa League.

After a non-playing period at PSV, Marcellis fought back at AZ and became one of the more reliable defenders in the league.

After impressing with PSV both in the UEFA Cup against Tottenham Hotspur and Fiorentina, where he played solid games against Dimitar Berbatov and Adrian Mutu, Marcellis caught the eye of not only Dutch football fans but also the Netherlands U-21 coach Foppe de Haan.

He received his first call-up under national team coach Bert van Marwijk for the 2010 FIFA World Cup qualification matches against Norway & Iceland.