The Spartan army was the military force of Sparta, one of the leading city-states of ancient Greece. The army stood at the centre of the Spartan state, whose citizens' primary obligation was to be good soldiers. Subject to military drill from infancy, the Spartans were one of the most feared military forces in world history. At Sparta's heyday in the 6th to 4th centuries BC, it was commonly accepted that "one Spartan was worth several men of any other state."

The first reference to the Spartans at war is in the Iliad, where they participate among the other Greek contingents. Like the rest of the Mycenaean armies, it was composed largely of infantry, equipped with short swords, spears, Dyplon and a simple rounded bronze shield. This was an age of heroic warfare with simple tactics, often little more than a general charge and a great deal of killing — it was common for entire armies to be chased down and killed after a rout. The basic tactic of battle was "free for all."

War chariots were used by the elite, but unlike their counterparts in the Middle East, they appear to have been used mostly for transport, with the warrior dismounting to fight on foot and then remounting it to withdraw from combat, although some accounts show warriors throwing their spear from the chariot before dismounting.