In Southeast Asia, the marginalization of children remains a huge concern in achieving inclusive early childhood care and development (ECCD). Twenty-five million children living in multidimensional poverty (United Nations Children’s Fund East Asia and Pacific, 2019) are in a disadvantaged position to receive high-quality ECCD programs, and therefore not only is their growth and development at risk but, in the long run, that of society in general as well. SEAMEO identified two of its seven priority areas as achieving universal early childhood care and education, and addressing barriers of inclusion by 2035. This regional study, which seeks to identify ways of achieving inclusive ECCD among marginalized children in Southeast Asia, supports these priority areas and, at the same time, shares the prospect of Sustainable Development Goal 4 to “ensure inclusive and equitable quality education and promote lifelong learning opportunities for all”.