UNICEF is seeking Expressions of Interest (EOI) from reputable peer-reviewed academic journals and publishers to collaborate on the publication of a Special Journal Collection focused on Implementation Research (IR) for Health Equity and Primary Health Care (PHC), with emphasis on immunization (including zero-dose children) and integrated childhood non-communicable disease (NCD) Programmes. The purpose of this EOI is to identify journals with the editorial expertise, publishing infrastructure, and global reach required to manage and publish a high-quality, open-access Special Collection of UNICEF-supported implementation research.