Intentionally modified teeth provide lasting evidence of cultural behavior and, when combined with archaeological, demographic, morphological and biochemical information, can provide significant insight into patterns of human behavior and interaction in prehistory. This chapter explores the origin and social context of modified teeth during the Mississippian period (AD 900–1400) in North America. The majority of examples are from sites associated with Cahokia, the preeminent Mississippian cultural center in eastern North America. New examples have increased the number of known cases of dental modification and the number of recognized modification styles. More important, they provide critical contextual and demographic information for the practice of dental modification and confirm a strong association of modified teeth with women. When considered in light of strontium isotope ( 87Sr/ 86Sr) data and evidence for biological relatedness, this chapter considers the movement of women and their role in creating biological and social relationships across regions during this period.