This article presents a correspondence between the mode of weapons acquisition by armed opposition groups and the form of a civil war. The mode of arms acquisition is affected by two factors—availability and control over the acquisition process. Variations in the mode of arms acquisition correspond to three types of insurgency: led by a single and organized group, warlordism, and disorganized armed bands. This article discusses how weapons acquisition is considered in the existing literature on arms and civil conflict, and examines the definitions of arms availability. It provides new insights on the availability and control of weapons in civil conflict and provides examples from Nepal, Iraq, and Afghanistan. The article concludes with an examination of the policy implications of its findings.