Behavioral health coding refers to the assignment of CPT and ICD-10 codes for mental health and substance use disorder services, including psychiatric evaluations, psychotherapy, medication management, crisis interventions, and substance use treatment. Behavioral health coding requires careful attention to provider type, service setting, time, modality, and diagnosis specificity. Accurate coding in this area is critical for proper reimbursement and for capturing the full clinical picture of a patient’s condition, particularly as behavioral health services continue to expand across care settings.