The Battle of Siikajoki (Finnish: Siikajoen taistelu) was fought between Swedish and Russian troops on April 18, 1808 at Siikajoki, near Oulu, Finland. During the first stage of the Finnish War the Swedish commander Wilhelm Mauritz Klingspor had decided to retreat from southern Finland, so that the Swedes would gain time, and more troops could be moved to Finland via Tornio. The move was also made in case the Danes would take the opportunity attack Sweden.
The Battle of Pyhäjoki, which had been fought two days earlier, was one of the first skirmishes of the war, but Siikajoki was the first major attempt to stop the advancing Russians. Carl Johan Adlercreutz had been appointed commander after count Löwenhjelm had been captured by the Russian at Pyhäjoki. The force commanded by Georg Carl von Döbeln was trying to cross the river of Siikajoki when the Russians caught up with his force. Von Döbeln decided to take a stance on the south bank of the river. He first ordered a counterattack, but were forced to pull back. At that moment, the Russian enter is opening up and the newly appointed General Adjutant Adlercreutz orders another attack, which throws the Russians back and halted the Russian advance.