Excavations at the site of Río Viejo in coastal Oaxaca, Mexico, yielded evidence of intensive cotton thread production during the Early Postclassic (a.d. 975–1220). Spindle whorls were recovered in relatively large quantities in and around houses at Río Viejo, indicating that thread production was interspersed with other household activities and residents likely produced enough thread for local use and for export. Measurements of coastal spindle whorls show that the Río Viejo thread was unique compared to other coastal and highland sites in Oaxaca and Mesoamerica beyond. I argue that this uniqueness may in part stem from the particular variety of cotton that they were spinning, but also might reflect an interregional demand for their thread. The whorl data are presented in multiple ways to compare to other sites where intensive thread production has been proposed. Here, I discuss the problems inherent in whorl calculations and make a call for more standardized recording, ideally with volumetric density measures. In the final section of the paper, I use mortuary data and other lines of evidence to re-evaluate the ethnohistorically-documented relationship between women and textile production. In coastal Oaxaca, the evidence suggests that thread production was not linked to specific gender identities in a way that is marked archaeologically. Instead, adult members of households in coastal Oaxaca materially emphasized a shared group identity over any specific gender-based identities. The production of thread was a broadly shared household-level practice that involved multiple producers, which both created and reinforced social bonds between residents and provided Early Postclassic residents with secure and comfortable access to highland goods, paving the way for the more developed thread production industry in the Late Postclassic period.