How does arms availability affect armed conflict? What implications does increased arms availability have for the organisation of armed groups involved in war against the state? This article explores these questions by looking into the civil war in Libya and the subsequent proliferation of weapons in the broader Sahel/North Africa region. Its argument is based on secondary sources: online databases, international organisations reports and news media. First, we examine the question of firearms in Libya in order to understand how changing conditions of weapons availability affected the formation of armed groups during different phases of war hostilities (February–October 2011). We highlight that, as weapons became more readily available to fighters in the field during this period, a process of fragmentation occurred, hindering efforts to build mechanisms that would allow control of the direction of the revolutionary armed movement. Next, as security continued to be a primary challenge in the new Libya, we consider the way in which unaccountable firearms and light weapons have affected the post-war landscape in the period from October 2011 to the end of 2013. Finally, we put the regional and international dimensions under scrutiny, and consider how the proliferation of weapons to nearby insurgencies and armed groups has raised major concern among Libya’s neighbours. Short of establishing any causal relationship stricto sensu, we underscore the ways in which weapons from Libya have rekindled or altered local conflicts, creating permissive conditions for new tactical options, and accelerating splintering processes within armed movements in the Sahara-Sahel region.