Aztec warfare concerns the aspects associated with the militaristic conventions, forces, weaponry and strategic expansions conducted by the Late Postclassic Aztec civilization of Mesoamerica, including particularly the military history of the Aztec Triple Alliance involving the city-states of Tenochtitlan, Texcoco, Tlacopan and other allied polities of the central Mexican region.

The Aztec armed forces were typically composed of a large number of commoners (yaoquizqueh) who possessed only basic military training, and a smaller but still considerable number of professional warriors belonging to the nobility (pipiltin) and who were organised into warrior societies and ranked according to their achievements. The Aztec state was centered around political expansion and dominance of and exaction of tribute from other city states, and warfare was the basic dynamic force in Aztec politics. Aztec society was also centered around warfare: every Aztec male received basic military training from an early age and the only possibility of upwards social mobility for commoners (macehualtin) were through military achievements - especially the taking of captives (maltin). The sacrifice of war captives was an important part of many of the Aztec religious festivals. Warfare was thus the main driving force of both the Aztec economy and religion.