This study empirically investigates the effect of factor mobility, specifically, labour mobility and capital mobility and income inequality on regional integration among the East African Community (EAC) Partner States. The research utilised an explanatory design and implemented a quantitative panel data methodology including 4 EAC countries, over a period of ten years. Data were examined utilising dynamic panel Generalised Method of Moments (GMM) estimation, with specification and instrument validity confirmed through standard diagnostic tests. The regression analysis indicated that the lagged level of regional integration, labour mobility, capital mobility and income inequality, all had favourable and statistically significant effects on the regional integration. Higher labour mobility strengthened cross-border labour market linkages and people-to-people connections; increased capital mobility deepened financial and investment integration; and income inequality was positively associated with integration, suggesting that regional integration has so far advanced alongside, rather than resolved distributional imbalances. These findings highlight the significance of promoting factor mobility while simultaneously addressing inequality, to foster deeper and more sustainable regional integration. Policymakers and regional institutions are urged to prioritise full implementation of free movement commitments, harmonisation of financial regulations and inclusion-oriented policies that ensure the gains from integration are broadly shared across and within the EAC Partner States.