Controlled substances, such as benzodiazepines, narcotic pain medications, and stimulants, can be helpful in the treatment of a wide variety of mental and physical conditions. In order to limit the improper use and abuse of these medications, the state and federal governments regulate how controlled substances are prescribed, distributed, and dispensed. Telemedicine physicians are often reluctant to utilize controlled substances out of fear and uncertainty of the rules. This represents a barrier to the expansion of telemedicine practice and development of new systems within accountable care organizations, resulting in patients being deprived of opportunities to obtain appropriate treatments. This article briefly defines and reviews online prescribing, controlled substances (history, current practices), telehealth (general, videoconferencing), and legal/regulatory practices (state, federal). Cases are provided to informally stratify the prescribing landscape and risk into categories of low, medium, and high risk of prescribing and to illustrate cases in which prescribing would probably require a policy change. The policy landscape pertaining to the prescription of controlled substances via telemedicine is complex and confusing to many. This primer for clinicians, administrators, and health care administrators provides information and an approach to evaluate issues and make decisions. It is intended to encourage further discussion and advocacy for policies that facilitate, rather than inadvertently impede, appropriate prescription of controlled substances via telemedicine. Clinicians, professional organizations, and telehealth organizations need to collaborate with others to adjust policies to improve access. More research on clinical care (best practices, barriers/obstacles) related to online prescribing is needed and how online prescribing is working and/or not working (e.g., barriers are arising).