[영문]This paper explores the impact of policies and institutions on unemployment in OECD countries over the pastdecades. Reduced-form unemployment equations, consistent with standard wage setting/price-setting models, areestimated using cross-country/time-series data from 21 OECD countries over the period 1982-2003. In the“average” OECD country, high and long-lasting unemployment benefits, high tax wedges and stringentanti-competitive product market regulation are found to increase aggregate unemployment. By contrast, highlycentralised and/or co-ordinated wage bargaining systems are estimated to reduce unemployment. These findingsare robust across specifications, datasets and econometric methods. The paper also finds evidence of interactionsacross policies and institutions, as well as between institutions and shocks. Some specific interactions across policiesand institutions are found to be particularly robust, notably between unemployment benefits and public spending onactive labour market programmes as well as between statutory minimum wages and the tax wedge. Finally, it isshown that macroeconomic conditions also matter for unemployment patterns, with their impact being shaped bypolicies.