The conflicts between herdsmen and farmers have a long history in West Africa, predating the current insecurity challenges, but only becoming more dangerous in recent years and threatening the fragile security and stability of the sub-region. In particular, Nigeria, Ghana, Ivory Coast, Senegal, Mali, Mauritania, Niger, and Chad have become notable for herders/farmers conflicts. The Global Terrorism Index (GTI) report of 2017, estimated that 3000 lives were lost between 2010 and 2016 to Fulani herders and farmers conflicts across four countries in the sub-region. As these conflicts increase in frequency, intensity and geographical scope, thousands have been killed and tens of thousands forcefully displaced and properties, crops and livestock worth millions of dollars destroyed. These conflicts have also assumed dreadful transnational dimension as some of the attackers who are mostly Fulani are drawn from other West African countries to fight in affected countries like Nigeria, Mali, Ghana, Ivory Coast and Niger. The transnational dimension of these conflicts has largely been ignored and so also the regional peacebuilding response. Drawing on evidence from countries of the sub-region, the study will examine the transnational dimension of the conflicts and the imperatives of peacebuilding within a regional framework. This will be done by examining how the ECOWAS Commission can be used to monitor and regulate international transhumance pastoralism and fight illicit arms trafficking in accordance with relevant international instruments, including ECOWAS Protocols.