Hammar may refer to:
Hammar (surname) Hammar Marshes, a large wetland complex in Iraq Lake Hammar, saline lake in Iraq Hammar, Kristianstad, a locality in Skåne County, Sweden Hammar, Askersund, a locality in Örebro County, Sweden Hammar experiment, experiment to test the aether drag hypothesis
See also Hamar, a town in Norway Hamar (disambiguation)