The successful closure of arms control negotiations today is conditional on the commitment of many more states than during the Cold War. The question of what determines states’ positions on arms control has therefore become increasingly relevant. Multiple scholars have identified external security threats by other states as the key explanatory factor of opposition to arms control, but empirical evidence hereof is so far limited to a small set of cases. Against this backdrop, this article carries out a global examination of the effect of external threats in the form of interstate disputes and rivalries on state support for arms control. This analysis is facilitated by a novel measure of arms control support that combines United Nations General Assembly voting data with manual coding of 1,178 resolutions. Across a variety of model specifications, the results do not show any significant effect of external threats on support for arms control. This article argues that this means either that the two variables are not related at all, or that two opposing mechanisms cancel out each other: arms control not only entails costs, but also benefits for states that face external threats, as it limits both states involved in a rivalry or dispute. Either way, this study challenges the notion that there is a strictly negative relationship between external threats and arms control support and thus contributes to our understanding of arms control and foreign policy making in general.