Christian Hammer (born Cristian Ciocan) is a Romanian-German professional boxer who held the WBO European heavyweight title three times between 2012 and 2018.

He turned pro in Germany in 2008, but lost against Robert Gregorin his professional debut.

In 2015, he lost to British future world champion, Tyson Fury for the WBO International Heavyweight title.

He held the WBO European Heavyweight title, which he won from Erkan Teper in 2016.

On March 2, 2019, Hammer fought title contented Luis Ortiz.