The Battle of Ajnadayn, fought on July 30, 634, in an unknown location close to Beit Guvrin in present day Israel, is the first major pitched battle between the Byzantine (Roman) Empire and the army of the Arabic Rashidun Caliphate.

The result of the battle is a decisive Muslim victory.

The details of this battle are mostly known through Muslim sources, such as 9th century historian Al-Waqidi.