The Battle of Yarmouk is a major battle between the Muslim forces of the Rashidun Caliphate and the armies of the Eastern Roman-Byzantine Empire.

The battle consists of a series of engagements that lasts for six days in August 636, near the Yarmouk River, along what is today the border between Syria and Jordan, southeast of the Sea of Galilee.

The result of the battle is a complete Muslim victory that ends Byzantine rule in Syria.

The Battle of Yarmouk is regarded as one of the most decisive battles in military history, and it marks the first great wave of Islamic conquests after the death of prophet Muhammad, heralding the rapid advance of Islam into the Christian Levant.In order to check the Muslim advance and to recover lost territory, Emperor Heraclius had sent a massive expedition to the Levant in May 636.

As the Byzantine army approaches, the Muslims retreat from Syria and regroup all their forces at the Yarmouk plains close to Arabia where, after being reinforced, they defeat the numerically superior Byzantine army.

The battle is also considered to be one of Khalid ibn al-Walid's greatest military victories.

It cements his reputation as one of the greatest tacticians and cavalry commanders in history.