This chapter covers how therapists can help clients with ADHD to develop organizational systems. Information is presented on how to help clients develop a system for sorting mail, reducing the chance that important mail and bills will be misplaced. Worksheet 2: Steps for Sorting Mail and Worksheet 3: Developing an Organizational System are introduced. The chapter discusses how to develop systems for other items that might be problematic for the client with ADHD, including papers, electronic files, emails, and household items. A case vignette is provided to illustrate the techniques.