The San Pedro oases, one of the few habitable locales in northern Chile’s Atacama Desert, have been a focus of human occupation for some 4000 years. During the Middle Period (AD 500–1000), populations in the oases grew, perhaps as a result of the incorporation of local communities in the Tiwanaku sphere of influence. Intensive bioarchaeological, radiometric, and isotopic analysis of hundreds of well-preserved skeletons from the oases’ numerous cemeteries has revealed a marked diversity of lifeways, some that conform to expectations and others that defy homogenizing narratives. This work also raises questions about the scales and units of bioarchaeological analysis, encouraging certain reconsideration but also opening new possibilities for future research.