There is a scarcity of systematic data regarding the military equipment of rebel groups engaged in intrastate conflicts. This empirical gap has impeded the rigorous evaluation of (formal) theories concerning militarized interactions between governments and rebel groups. To address this deficiency, we have developed the Rebels' Armament Dataset (RAD). This dataset provides detailed information on the military arsenals of 270 groups over the period from 1989 to 2020, categorizing 15 different types of small arms, light weapons, explosives, and major weapons. In this article, we introduce RAD, compare it with existing datasets, elucidate the data collection process, present an initial overview of the information contained in it, and apply the data to examine civilian suffering in civil wars. Although this dataset is merely an initial step that can be expanded as additional public information becomes available, RAD offers the first organized compilation of data on the armament levels of rebels.