Artemios "Demis" Ventouris Roussos (Greek: Αρτέμιος "Ντέμης" Βεντούρης Ρούσσος, born June 15, 1946) is a Greek singer and performer who had a string of international hit records as a solo performer in the 1970s after having been a member of Aphrodite's Child, a progressive rock group that also included the well renowned Vangelis. He has sold over 60 million albums worldwide.

Roussos was born and raised in Alexandria, Egypt, in a family where both father George (engineer Yorgos Roussos) and mother Olga were of Greek origin. His parents lost their possessions during the Suez Crisis and consequently decided to move to Greece.