United Nations sanctions are authorized by the international body that is legally charged with the maintenance of international peace and security, the UN Security Council. They are grounded in provisions of the UN Charter. However, only a fraction of all international sanctions are mandated by the UN. One of the findings of this article, which is based on data collected by the Targeted Sanctions Consortium (TSC), is that the large majority of UN sanctions are preceded by non-UN sanctions, particularly sanctions by the United States and the European Union. Furthermore, it is common practice, particularly by the US and the EU, to add sanction provisions of their own to UN sanctions. As a result, for most UN sanctions, there are also non-UN sanctions against the same targets. Such combined sanction regimes add restrictions imposed by only some governments to those that all countries have to implement. Combined sanction regimes are therefore potentially more effective in achieving the targeted outcome than UN sanctions, which represent the lowest common denominator achievable among the members of the UN Security Council. On the other hand, combined sanction regimes might suffer from a type of ‘sanctions fatigue’. A growing number of states outside of the West are openly opposed to unilateral sanctions. Adding non-UN sanctions to UN sanctions might reduce their willingness to support UN sanctions. The TSC data, however, does not support such a contention. Rather, the data indicates that combined sanction regimes are more effective than stand-alone UN sanctions. Still, the US and EU governments—as the main drivers of sanctions policy in general and UN sanctions in particular—need to be aware of this criticism in order not to unwittingly undermine the UN sanctions instrument.