A Nurse Practitioner (NP) is a registered nurse who has completed specific advanced nursing education (either a Master's or a Doctorate degree) and training in the diagnosis and management of common as well as complex medical conditions. Nurse Practitioners are generally licensed through nursing boards rather than medical boards as they provide advanced nursing services. In the U.S., nurse practitioners are sometimes considered "mid-level" providers similar to physician assistants (PAs), though often NPs practice independent of physician supervision. Nurse Practitioners provide a broad range of health care services.

Nurse Practitioners treat both physical and mental conditions through comprehensive history taking, physical exams, physical therapy, ordering tests and therapies for patients, within their scope of practice. NPs can serve as a patient's primary health care provider, and see patients of all ages depending on their designated scope of practice.

In the United States, NPs are licensed by the state in which they practice, and have a national board certification (usually through the American Nurses Credentialing Center or American Academy of Nurse Practitioners). Nurse Practitioners can be trained and nationally board certified in areas of FNP (Family Nurse Practitioner), Pediatrics, including Pediatric Acute/Chronic Care, Pediatric Critical Care, Pediatric Oncology and general Pediatrics (PNP), Neonatology (NNP), Gerontology (GNP), Women's Health (WHNP), Psychiatry & Mental Health (PMHNP), Acute Care (ACNP), Adult Health (ANP), Oncology (ONP), Emergency Medicine (as FNP or ACNP), Occupational Health (as ANP), etc. These programs, offered by many universities with a School of Nursing, graduate-level nursing programs upon completion students may be awarded a Master of Science in Nursing (MSN) or Doctor of Nursing Practice (DNP) degree.

In regard to level and scope of practice, each state certifies nurse practitioners thus their scope of practice can differ depending on the state.