A registered nurse (RN) is a nurse who has graduated from a nursing program and met the requirements outlined by a country, state, province or similar government-authorized licensing body to obtain a nursing license.An RN's scope of practice is determined by legislation, and is regulated by a professional body or council.

Registered nurses are employed in a wide variety of professional settings, and often specialize in a field of practice. They may be responsible for supervising care delivered by other healthcare workers, including student nurses, licensed practical nurses (except in Canada), unlicensed assistive personnel, and less-experienced RNs.

Registered nurses must usually meet a minimum practice hours requirement and undertake continuing education to maintain their license. Furthermore, there is often a requirement that an RN remain free from serious criminal convictions.