Pig avoidance is among the most famous and well studied of the customs described in the Hebrew Bible. Commonly the ban on consuming pork has been considered evidence of the importance of dietary prohibitions in establishing boundaries between Israel and neighboring groups. I argue, however, that differentiation from other ethnicities by means of diet was not the only function that the pig prohibition served in ancient Israel. In fact, the relevant biblical texts are as much, if not more, concerned with employing the pig prohibition as a device by which cultic norms as well as dietary customs within the Israelite community were standardized. With the accounts of the Maccabean rebellion in the second century BCE, the pig assumes a greater significance in identity formation, but even in these traditions, the relationship between pig avoidance and ethnic boundaries is more complex than is often assumed. Detailed analysis of the references to the pig in Lev 11, Deut 14, Isa 56–66, and 1 and 2 Maccabees, along with the study of archaeological evidence and comparative materials from the ancient Near East and ancient Mediterranean more broadly, reveals the multiplicity of factors that shaped the emergence of pig avoidance as a central custom in ancient Judaism.