Frederikshavn forenede Idrætsklubber (also known as FfI or Frederikshavn fI) is a Danish sports club based in Frederikshavn. The club has branches in football, handball, swimming, gymnastics and wrestling.
The football team spent a total five seasons in the top-flight Danish 1st Division during the 1960s and 1970s. Its most famous player through time is Harald Nielsen.