The Batavii (or Batavi, Batavians) were a Germanic, or possibly Celtic tribe reported by Julius Caesar and Tacitus to have lived around the Rhine delta, in the area which is currently the Netherlands. This led to the Latin name of Batavia.

They were mentioned by Julius Caesar in his commentary Gallic Wars, as living on an island formed by the Meuse River after it is joined by the Waal, 80 Roman miles from the mouth of the river. He said there were many other islands formed by branches of the Rhine, inhabited by savage and barbarous nations, some of whom were supposed to live on fish and the eggs of sea-fowl.

Later, Tacitus described the Batavians as the most brave of the tribes of the area, inhabiting not much territory on the Rhine but an island in it. They were formerly part of the Chattians but moved after a feud to become part of the Roman Empire. He said they retained the honour of the ancient association with the Romans, not required to pay tribute or taxes and used by the Romans only for war. Well-regarded for their skills in horsemanship and swimming, the Batavians provided a contingent for the Emperor's Praetorian Guard. Tacitus named the Mattiaci as a similar tribe under homage, but on the other (Germanic) side of the Rhine. The areas inhabited by the Batavians were never occupied by the Romans, as the Batavians were allies.

Despite the alliance, in 69 AD, a Batavian rebellion led by Claudius Civilis arose, which was defeated by the Romans the following year.

After the 3rd century CE, the Batavians are no longer mentioned, and they are assumed to have merged with the neighbouring Frisian and Frankish people.

The Batavians became regarded as the eponymous ancestors of the Dutch people. The Netherlands were briefly known as the Batavian Republic. Moreover, in the time Indonesia was a Dutch colony, the capital (now Jakarta) was named Batavia.

A map (http://www.livius.org/a/1/germania/germinf_map.gif) of the Roman province Germania Inferior and neighbouring tribes.