This report describes the capacity of U.S. nonprofits to mobilize in international development and assistance, promotion of international understanding, and international affairs. It is the first systematic national study of international nonprofits using descriptive statistics and data on charitable nonprofits obtained from the National Center for Charitable Statistics (NCCS) at the Urban Institute. Findings confirm the central role of international nonprofits in supporting foreign causes and distributing aid around the world. Government's increasing reliance on non-governmental organizations (NGOs) to carry out foreign aid programs is also detailed.