Frederikshavn is a Danish town in Frederikshavn municipality, Region Nordjylland, on the northeast coast of the Jutland peninsula in northern Denmark. Its name translates to "Frederik's harbour". It was originally named Fladstrand.

The town has a population of 23,156 (1 January 2014), and is an important traffic portal with its ferry connections to Sweden and Norway. The town is well known for fishing, and its fishing and industrial harbours. The Danish term "frederikshavner" (lit. "Someone from Frederikshavn") is used to denote a quality plaice, probably the most popular fish eaten in Denmark.