Marcel Sieberg (born 30 April 1982 in Castrop-Rauxel, North Rhine-Westphalia) is a German road racing cyclist, who currently rides for UCI WorldTeam Bahrain–Merida.
However, in August 2018 it emerged that the pair would go their separate ways for 2019, with Sieberg signing a one-year deal with Bahrain–Merida, taking on a role as a lead-out man for another German sprinter, Phil Bauhaus.