This article empirically tests existing theories that have been used to explain the presence of nonprofits. A framework was developed from existing literature to test the explanatory power of competing theories about the presence of nonprofits. The cross-national framework of this study is intended to explore the explanatory power of existing models for settings other than the national culture in which most of them were created. The analysis revealed a number of detailed findings about socioeconomic and institutional determinants of nonprofit service provision. In general, theories that emphasize demand-side or “need” explanations for nonprofits were less well supported than supply-side and institutional theories. The article concludes with recommendations for future cross-national studies of nonprofit activities. © 2011, Taylor & Francis Group, LLC. All rights reserved.