Over the past decade, many low- and middle-income countries have made expanding health coverage a national priority. During 2021, 11 countries took part in the JLN Learning Collaborative on Population Targeting, which focussed on population targeting as a critical component for expanding effective coverage to unserved groups. This page outlines the key outputs and outcomes of this work. This handbook - and the associated collection of implementation tools (institutional coordination, and data linkage) - provides a curated collection of practical tools and guidance for health agencies who wish to improve the accuracy and efficiency of these ‘population targeting’ functions. It is the result of a year of peer-led learning and co-production by over 40 public officials and other practitioners from 11 countries, who formed the JLN Learning Collaborative on Population Targeting. Drawing on the unanimous experience of this group that the best solutions involve close collaboration with other, nonhealth agencies (such as those operating cash transfer and other social protection programs), the focus is on two interrelated themes: (i) institutional coordination between health and non-health agencies, and (ii) data linkage between health and non-health agencies for population targeting.