The Theater War (Swedish: Teaterkriget), Cowberry War, Cranberry War or Lingonberry War (Norwegian: Tyttebærkrigen, Danish: Tyttebærkrigen), is a brief war between Denmark–Norway and Sweden, starting on September 24, 1788, formally lasting until July 9, 1789.
Although the decision to launch the attack is taken in Denmark, the majority of the attacking soldiers are Norwegians from the Danish-Norwegian army.
The attack is directed towards the region known as Bohuslän in Sweden, and is supposed to act as a diversion to relieve Russia, who is an ally of Denmark–Norway and had recently been attacked by Sweden (Gustav III's Russian War).
This forces Denmark–Norway to honor their alliance between the two states that had been signed in 1773.