This cross-national investigation examines hypotheses derived from two major alternative perspectives on the determinants of trust in contemporary societies. Is a society's level of generalized trust a function of its ethnic composition, or of its type of governance and political system? The argument that social diversity (ethnic, linguistic, and religious) leads to lower levels of trust, at least in the short run, is assessed with cross-national data (N = 98). Two hypotheses derived from this perspective are not confirmed. The alternative rational governance argument, which holds that trust is a function of rational governance, stable democracy, and civil rights is also assessed. Three hypotheses derived from this political perspective reveal mixed results. The findings highlight the complex interplay of multiple factors in shaping a society's overall level of generalized trust.