Nigeria’s adoption of the World Health Organization’s Joint External Evaluation (JEE) and National Action Plan for Health Security (NAPHS) will strengthen its national health security efforts. Writing in Health Security, experts at Resolve to Save Lives document the process of completing a JEE with partners in Nigeria in 2017 and subsequently creating a NAPHS to improve prevention, detection, and response in 2018. The process included developing a 5-year implementation plan, creating management teams, drafting outbreak legislation and training professionals at subnational and local levels. Strategic use of international assistance, coupled with reviews of major outbreaks, will strengthen Nigeria’s ability to prevent and respond to health security threats, and regular review and adaptation of its 5-year plan will be essential to ensure sustained progress.