Many individuals diagnosed with a mental illness will also struggle with substance use in their lifetime. Yet, interventions for specific comorbidities are seldom used and scarcely researched. The following review will explore the efficacy of mindfulness-based therapies for obsessive-compulsive (OCD) and substance use disorders (SUDs), respectively, in order to inform the development of new interventions for this dually-diagnosed population. Based on the literature, two promising therapies stand out: Acceptance and Commitment Therapy (ACT) as well as a group-based therapy called Mindfulness-Based Relapse Prevention (MBRP). Key skills espoused by mindfulness-based approaches will be reviewed, and a combined intervention approach is proposed.