An estimated one billion people worldwide live with disabilities and, of the world’s poorest people, one in five live with disabilities. Pledging to leave no one behind, the Agenda for Sustainable Development recognizes that development programming must be inclusive of people with disabilities. Data is the key to identifying challenges and solutions that can improve the lives of persons with disabilities. This Guidebook supports the implementation of the Washington Group Short Set (WG-SS) – a set of questions designed to identify (in a census or survey format) people with a disability – in multi-topic household surveys, towards improving the collection of disaggregated disability data. The first section presents an overview of the disability definitions in the sociopsychological literature, exploring how disability is defined and who is considered disabled. The second section looks at three different methods for capturing disability in multi-topic household surveys: the Washington Group (WG) question sets, the World Health Organization (WHO) survey instruments for disabilities, and the Demographic and Health Surveys (DHS) module on disabilities. The third section presents the six core WG-SS functional domains, ‘seeing’, ‘hearing’, ‘walking’, ‘cognition’, ‘selfcare’, and ‘communication’, that are intended for the general population five years of age and above. Finally, the Guidebook offers a series of recommendations for ensuring the improvement of disability data collection in multi-topic household surveys, such as incorporating the WG-SS as a subsection of the health section, and avoiding the use of mental health questions and terms that carry negative connotations, such as ‘disabilities’, ‘handicaps’, and ‘suffering’, which may result in the underreporting of conditions.