We examine how religio-ethnic identity, individual religiosity, and family members’ religiosity were related to preferred family size in Nepal in 1996. Analyses of survey data from the Chitwan Valley Family Study show that socio-economic characteristics and individual experiences can suppress, as well as largely account for, religio-ethnic differences in fertility preference. These religio-ethnic differentials are associated with variance in particularized theologies or general value orientations (like son preference) across groups. In addition, individual and family religiosity are both positively associated with preferred family size, seemingly because of their association with religious beliefs—beliefs that are likely to shape fertility strategies. These findings suggest the need for improvements in how we conceptualize and measure supra-individual religious influence in a variety of settings and for a range of demographically interesting outcomes.