This presentation offers an in-depth overview of the assessment and diagnosis of obsessive-compulsive disorder (OCD), with a focus on individuals served in community mental health settings. Given the high rates of misdiagnosis and underdiagnosis in these populations, attendees will gain practical tools for identifying core features of OCD, differentiating it from related conditions, and understanding how systemic and cultural factors impact diagnostic accuracy. The presentation will also provide an overview of evidence-based treatments for OCD, including exposure and response prevention (ERP), and will address common but ineffective or contraindicated approaches. Emphasis will be placed on increasing access to appropriate, effective care through accurate diagnosis and referral. This training is intended for field-based mental health and outreach workers in Los Angeles County.