This article argues that social welfare policies may reduce international and domestic terrorism. Social policies likely affect terrorism in offsetting ways but, on balance, should diminish preferences for terrorism by reducing economic insecurity, inequality, poverty, and religious-political extremism. Thus, countries with more generous welfare provisions should suffer fewer terrorist attacks on their soil and have fewer of their citizens perpetrate terrorism. Supporting this argument, cross-sectional estimation reveals that a country's welfare efforts negatively correlate with transnational or total terrorist incidents on its soil, as well as transnational terrorism perpetrated by its citizens. Pooled cross-section time-series estimation reveals that several measures of welfare effort reduce the incidence of transnational terrorism in countries, robust to a range of estimators and controls. Such findings suggest that strengthening social policies at home and abroad may not only serve redistributive or development goals but also help combat terrorist violence. (Contains 3 figures, 4 tables and 10 footnotes.)