The proliferation of small arms and light weapons is and has remained one of the major security challenges Nigeria, Africa and the World at large is currently facing. The thrust of this paper is on the impact of uncontrolled proliferation, stockpiling, trafficking, availability and usage of these arms on Nigeria‟s national security as it is believed to fuel alarming levels of armed crime, communal conflict, political instability, social unrest as well as making all the geo-political zones of the country to be flooded with small arms. The paper further argues that the inability of the Nigerian government and its law enforcement agencies to check the menace has led to a major challenge of security, as it was revealed that previous and current efforts at tackling the issue has not yielded much efforts as only a few number of seizures of illegal arms has been made hence the proliferation continues to sustain and exacerbates armed conflicts within the country. The study is anchored on the realist and failed state theories using secondary data, literature evidence, descriptive and historical methodology. Findings reveal that the impact of small arms and light weapons on the society is too grave and devastating to be treated with kid‟s glove as it leads to massive loss of lives and properties, erodes social capital, facilitate corruption and climate of impunity. The paper recommends that the government must rise up to the challenges of tackling the menace with all seriousness and commitment.