Mali and Nigeria are both faced with the presence of insurgencies, militia, terrorism and other violent non-state actors (VNSAs), who perpetrate large-scale violence; thus, creating daunting security challenges in these countries. This goes pari passu with the proliferation of small arms and light weapons (SALWs) in these countries. While these countries have inherent human security challenges, this spate of insecurity will not only inhibit the quest for human security, but further deteriorate it. Thus, this paper examines the interrelationship between arms proliferation, violent conflicts and insecurity in these countries and their implication on human security. The study is anchored on the State Collapse theory and the Ex-post Facto research design. The Documentary Observation method of data is utilised; hence, data is generated from secondary sources such as academic publications, organisational publications, databases, etc. For data analysis, the study adopts the Causal Analysis and Process Tracing methods of data analysis. The study found that the proliferation of SALWs and violent conflicts complement each other in Mali and Nigeria, thus, creating high-scale insecurity challenges in both countries. It also found that the implications of this state of affairs on human security are enormous in these countries; particularly in the aspects of physical security, food security, economic security, environmental security and political security. On these bases, the study advocates for relevant stakeholders such as the governments, ECOWAS, religious organisations and traditional institutions to play key roles in addressing the menace