The Battle of Orsha (Lithuanian: Oršos mūšis, Belarusian: Бітва пад Оршай, Polish: bitwa pod Orszą, Ukrainian: Битва під Оршею), was a battle fought on 8 September 1514, between the allied forces of the Grand Duchy of Lithuania and the Crown of the Kingdom of Poland, under the command of Lithuanian Grand Hetman Konstanty Ostrogski; and the army of the Grand Duchy of Moscow under Konyushy Ivan Chelyadnin and Kniaz Mikhail Golitsin. The Battle of Orsha was part of a long series of Muscovite–Lithuanian Wars conducted by Muscovite rulers striving to gather all the former Kievan Rus' lands under their rule.

According to Rerum Moscoviticarum Commentarii by Sigismund von Herberstein, the primary source for information on the battle, the much smaller army of Lithuania–Poland (under 30,000 men) defeated a force of 80,000 Muscovite soldiers, capturing their camp and commander. These numbers and proportions have been disputed by some modern historians.