The purpose of this study is to evaluate the feasibility, acceptability, and potential usefulness of using a mobile app (nOCD) for treatment of OCD in a sample of 25 adults (ages 18-65). nOCD is a free iOS/Android app that provides EX/RP-consistent treatment strategies. The study team will evaluate the effect of the app using gold-standard clinician-administered and self-report measures. Prior to downloading the app, participants will receive 4 (up to 5) in-person visits and receive brief weekly phone check-in. The long term goal of this line of research is to increase access to evidence-based treatment and to ultimately reach more patients giving them access to tools to reduce their OCD symptoms and improve their quality of life.