This chapter examines the concept, historical evolution, and multifaceted contributions of interregional diaspora communities, whose networks and mobility extend beyond traditional bilateral migration corridors. It situates interregional diasporas within theoretical frameworks of transnationalism, social remittances, diaspora diplomacy, and network theory, highlighting their economic, political, cultural, and humanitarian roles. Through case studies—including the Indian diaspora in East Africa and the UK, the Filipino diaspora in the Gulf and North America, the Somali diaspora across multiple continents, and the Bangladeshi diaspora in the UK—the chapter illustrates how cross-regional linkages shape development, identity, and diplomacy. It also addresses challenges such as identity negotiation, political tensions, remittance dependency, and elite capture. The chapter concludes by assessing policy frameworks, institutional engagement, and emerging trends, including digital connectivity, climate-induced mobility, and multipolar geopolitics. It identifies key research gaps in measuring diaspora impacts, particularly in complex interregional contexts.