Inherent to warfare are armed conflict and an acknowledged enemy against whom one is fighting. Yet relations with that enemy are defined as much in the discourse of war as on the battlefield. Words mobilize both martial and symbolic power by identifying the antagonist and morally justifying one’s own cause at the expense of the opposition. Scholars have long been aware that the Spanish-led conquest of the Americas was a discursive phenomenon as well as a military one. However, the influence of just war philosophy on conquistadors’ representations of their indigenous foes has remained largely unexplored. In repelling the Spanish-led invasion, Highland Maya communities employed various strategies that drew on the cunning and deceit that they so highly valued in their warriors. The Spaniards, however, were highly critical of such conduct, which did not conform to their traditional conceptions of just war. To them, such comportment marked their opponents as insurgents resisting not only their rightful place in the Spanish Empire but also civilization more broadly. In condemning their Highland Maya enemies as an ethical “other,” the conquistadors articulated a just cause for their conquest waged to subdue a rebellious population. By asserting moral superiority in the face of a treacherous and malevolent adversary, they legitimized not only their quest for power in the Americas but also the often excessively violent means that they employed to this end.