The battle of Laodocium (423 or 422 BC) was a clash between two Peloponnesian cities, fought during a brief armistice between Athens and Sparta (Great Peloponnesian War). The battle was fought between the armies of Tegea, in the centre of the Peloponnese, and Mantinea, in the north-east of the Peloponnese. In the wider conflict Tegea was an ally of Sparta, while Mantinea had fought alongside Sparta earlier in the war, but then sided with Athens.
The battle was fought at Laodocium, in the territory of Orestheum. This was close to the site of the city of Megalopolis, founded in 371 BC as a counter-weight to Sparta, and located to the south-west of both Tegea and Mantinea. Thucydides describes it as happening in the winter of the ninth year of the war, placing it in the winter of 423-2 BC.
The battle itself was inconclusive. Each army was victorious on one wing and defeated on the other, and both sides erected a trophy to celebrate their victory. The Tegeans remained on the battlefield overnight, suggesting that they had had the best of the fighting, while the Mantineans retreated to Bucolion before erecting their trophy. Both sides suffered heavy losses during the fighting.