In 2011 the Grand Challenges in Global Mental Health initiative identified priorities that have the potential to make a significant impact on the lives of people with mental, neurological, and substance use disorders. Reduction of the cost and improvement of the supply of effective medicines was highlighted as one of the top five challenges. For low- and middle-income countries, improving access to appropriate essential medicines can be a tremendous challenge and a critical barrier to scaling up quality care for mental, neurological, and substance use disorders. Reduction of cost and improvement of the supply of effective medicines has the potential to significantly impact the lives of patients with these disorders. Improving Access to Essential Medicines for Mental, Neurological, and Substance Use Disorders in Sub-Saharan Africa is the summary of a workshop convened by the Institute of Medicine Neuroscience Forum in January 2014 in Addis Ababa, Ethiopia to discuss opportunities for achieving long-term affordable access to medicines for these disorders. This report examines challenges and opportunities for improving access to essential medicines in four critical areas: demand, selection, supply chains, and financing and pricing. The report also discusses successful activities that increase access to essential medicines both within Sub-Saharan Africa and in other developing countries, and considers the role of governments, nongovernmental organizations, and private groups in procurement of essential medicines for mental, neurological, and substance use disorders.