Immigration can expand labor supply and create greater competition for native-born workers. But immigrants may also start new firms, expanding labor demand. His paper uses U.S. administrative data and other data resources to study the role of immigrants in entrepreneurship. We ask how often immigrants start companies, how many jobs these firms create, and how these firms compare with those founded by U.S.-born individuals. A simple model provides a measurement framework for addressing the dual roles of immigrants as founders and workers. The findings suggest that immigrants act more as "job creators" than "job takers" and that non-U.S. born founders play outsized roles in U.S. high-growth entrepreneurship.