This study investigates the impact of the Aztec Triple Alliance on trade and economic activity in the region of Puebla-Tlaxcala during the Late Postclassic period (AD 1200–1519). Ethnohistorical sources describe the Aztec Triple Alliance as constantly at war with settlements in the Tlaxcala region. To weaken their Tlaxcalteca rivals, the Aztecs imposed a trade blockade to reduce the flow of resources into Puebla-Tlaxcala. This article uses archaeological evidence to evaluate the effectiveness of this blockade. It compares the types of obsidian used to manufacture lithic tools from Aztec-controlled sources with those used within Puebla-Tlaxcala. Information from the large center of Tepeticpac and the small obsidian workshop site of Cinco Santos II, both in the Tlaxcala domain, are compared to other sites in Central Mexico prior to and during the height of Aztec influence. The results show little difference in regional trade patterns: obsidian from Sierra de las Navajas and Otumba was used in proportions in the Tlaxcala region in the Late Postclassic similar to those used during earlier periods. If an embargo was attempted, it was largely unsuccessful in isolating Tlaxcala from broader regional distribution networks.