Marcel Hacker (born 29 April 1977, in Magdeburg) is a German rower.
Hacker won an Olympic bronze medal in 2000 in Sydney and became a world champion in 2002 in Seville.
In 2004, he won the Diamond Challenge Sculls for the second time (the premier event for single sculls) at the Henley Royal Regatta.
At the 2016 Summer Olympics in Rio de Janeiro, he competed in men's double sculls with teammate Stephan Krüger. They finished in 8th place.