The Battle of Oravais (Finnish: Oravaisten taistelu; Swedish: Slaget vid Oravais) was one of the decisive battles in the Finnish War, fought from 1808 to 1809 between Sweden and the Russian Empire as part of the wider Napoleonic Wars. Taking place in modern-day Vr in western Finland, it is sometimes regarded as the turning point of the Finnish War: the last chance for Sweden to turn the war to her advantage. It was the bloodiest battle of the conflict, along with the Battle of Svar, which some historians attribute to the exhaustion, resignation and desperation of the Swedish army: it was losing the war, and defeat led to its loss of Finland to Russia.

The Finnish War (Swedish: Finska kriget, Russian: Финляндская война, Finnish: Suomen sota) was fought between the Kingdom of Sweden and the Russian Empire from 21 February 1808 to 17 September 1809. As a result of the war, the eastern third of Sweden was established as the autonomous Grand Duchy of Finland within the Russian Empire. Other notable effects were the Swedish parliament's adoption of a new constitution and the establishment of the House of Bernadotte, the new Swedish royal house, in 1818.