Early childhood education serves as the cornerstone of lifelong development, shaping individuals’ cognitive, social, and emotional foundations. However, disparities in access, quality, and outcomes persist, posing a significant challenge to achieving equitable educational opportunities for all children. This comprehensive review paper explores socio-economic disparities in early childhood education, focusing on Nigeria and the United Kingdom (UK). Drawing from a systematic examination of research studies, government reports, and policy documents, this paper synthesizes key findings and compares the experiences of these two diverse regions. In both Nigeria and the UK, access disparities in early childhood education are evident. Nigeria grapples with a pronounced rural-urban divide, while the UK experiences regional variations in access. Quality disparities are also prevalent in both countries, with Nigeria facing infrastructure and teacher training challenges and the UK encountering funding and resource allocation issues. Furthermore, socio-economic factors influence parental engagement in early education, impacting children’s development in both contexts. The implications of these disparities are far-reaching, affecting individual children, families, and society as a whole. Addressing these disparities requires a multifaceted approach encompassing equitable policies, targeted interventions, and a sustained commitment from policymakers and stakeholders. This paper underscores the critical importance of early childhood education as a lever for promoting equity and social cohesion. The conclusion outlines policy imperatives, future research directions, and the imperative to create a brighter and more equitable future for the next generation. Societies can create an environment where every child can thrive regardless of socio-economic background by addressing disparities comprehensively. This review paper contributes to a deeper understanding of the global challenge of early childhood education disparities. It offers insights to inform policy and practice in diverse contexts.