This thematic brief provides essential information about persons with disabilities and guidance for incorporating an inclusive approach into development projects. It presents key definitions regarding disability status, including the different types of disabilities and the barriers that limit full participation. It also addresses fundamental concepts such as accessibility, reasonable accommodation, and universal design. The brief examines the main socioeconomic gaps affecting persons with disabilities, the relevant international legal framework, and the IDBs approach to this topic. For those who wish to explore the subject further, the brief refers to additional publications and resources. This thematic brief is part of a series of publications that provide information to help integrate a gender and diversity perspective into development projects.