Markus Grosskopf (born 21 September 1965) is a German musician best known as the bass guitarist, backing vocalist and a founding member of the power metal band Helloween.

He played bass on the first two albums of Edguy vocalist Tobias Sammet's project, Avantasia, issued in 2001 and 2002.

[3] Grosskopf's playing style has been known to include prominent basslines, and occasionally he has a solo such as in "Heavy Metal (Is the Law)" or "Eagle Fly Free", which is one of his most famous.

He regularly uses a pick for the more straightforward, simple bass lines, as in I Want Out or Just a Little Sign, and fingers for more lead-type playing, as on Eagle Fly Free or Halloween.

His playing style expanded on one of Helloween's more recent albums Keeper of the Seven Keys: The Legacy, where many more bass solos and lead parts are heard, like "Invisible Man", "Light the Universe" and even some slap bass on the first single "Mrs. God", as well as "Goin' Home" from Pink Bubbles Go Ape, where one can hear slap for the first time in Helloween's discography.