This module provides an overview of key concepts and practices related to treatment and interventions for individuals with dual diagnosis. The beginning sections provide important information related to treatment access for individuals with dual diagnosis, professional preparedness and training, and key principles for guiding the treatment process. The subsequent sections provide an overview of treatment approaches and promising treatment practices, as well as important information related to medication use and its cautions. The final section explores the importance of collaboration and coordinated service approaches among service providers and treatment specialists.