Gaby Koss (born 25 March 1978 in Munich, Germany) is a German classically trained soprano who has collaborated with metal and rock acts such as Haggard, Nota Profana and Equilibrium. She is the front singer of the bands Nota Profana and Theatre of the Night. She also has her own ensemble of renaissance, baroque and medieval folk music, Cantus Lunaris. In 2014, she started another band that goes by the name of Diskelion.
She has collaborated with several composers from England, Japan and Russia in the making of movie and TV-series soundtracks. Her collaborators include British composer JD Hermien, composer of the soundtrack for the US series War Wraiths.