The Battle of Blue Waters was fought at some time in the autumn of 1362 or 1363 on the banks of the Syniukha River, a left tributary of the Southern Bug, between the armies of the Grand Duchy of Lithuania and the Golden Horde. The Lithuanians won a decisive victory and finalized their conquest of the Principality of Kiev.

The Grand Duchy of Lithuania was a sovereign state in northeastern Europe that existed from the 13th century, succeeding the Kingdom of Lithuania, to the late 18th century, when the territory was suppressed during the 1795 partitions of Poland–Lithuania. The state was founded by Lithuanians, who were at the time a polytheistic nation of several united Baltic tribes from Aukštaitija, which by 1440, became the largest European state controlling an area from the Baltic Sea in the north to the Black Sea in the south.