The Battle of Ashmyany or Ašmena (Lithuanian: Ašmenos mūšis) was fought on 8 December 1432 at Ashmyany between the armies of Švitrigaila and Sigismund Kęstutaitis, two pretenders to the throne of the Grand Duchy of Lithuania during the Lithuanian Civil War (1432–1438).

Švitrigaila with several thousand troops (estimated to total about 40,000) marched out of Polatsk, where he was staying, and took Minsk, Kreva, Ashmyany, and was preparing to attack Vilnius.

Sigismund Kęstutaitis' Lithuanian and Samogitia army supported by Masurians from Drahichyn (estimated to total about 20,000) attacked Švitrigaila's Lithuanian and Russian troops supported by Tatars, led by Khan Sayid Ahmad I. Švitrigaila's Livonian Order allies did not arrive in time for the battle.

Although Sigismund Kęstutaitis won the battle, his army was also weakened and sp he could not pursue Švitrigaila and end the civil war.

The Lithuanian Civil War (1431–1435) ended with the 1435 Battle of Wilkomierz during which Švitrigaila's army was dealt a final defeat.