Which social, political and global factors affect the supply of labor to terrorist organizations? To answer this question, I propose a multivariate model at the national level which includes three classes of factors hypothesized to have a relationship with the supply of labor to terrorism. Drawing on motivation and political opportunism as explanations of terrorism, the three classes of factors are defined as social-structural, political-institutional, and global-capitalist contexts. The data for the dependent variables is obtained from 28 countries between 1991 and 1997. After applying the negative binomial regression model in a cross sectional time series analysis to the afore-mentioned factors, I found that political institutional factors and nations' position in the world system are related to the origins of terrorists.