A nurse's cap or nursing cap is part of the female nurse's uniform, introduced early in the history of the profession. The cap's original purpose was to keep the nurse's hair neatly in place and present a modest appearance. Male nurses do not wear caps.

In some schools, a capping ceremony presents new nursing students their caps before beginning their clinical (hospital) training.

The nurse's cap originated from a group of women in the early Christian era, called "deaconesses." These women were distinguished from other women during this time by white coverings worn on their heads. This particular head covering was worn to show that this group of women worked in the service of caring for the sick. Originally, this head covering was more of a veil, but it later evolved into a white cap during the Victorian era. It was during this era that women were required to keep their heads covered. The cap worn was hood-shaped with a ruffle around the face and tied under the chin, similar to cleaning ladies of that day. Long hair was fashionable during the Victorian era, so the cap kept the nurse's hair up and out of her face, as well as keeping it from becoming soiled.

The nurse's cap was derived from the nun's habit and developed over time into two types:

The nursing cap was originally used by Florence Nightingale in the 1800s.

Different styles of caps were used to depict the seniority of the nurse, the frillier and longer the more senior the nurse.

The nursing cap is a nearly universally recognized symbol of nursing. It allows patients to quickly identify a nurse in the hospital from other members of the health team. Additionally, some designs of caps serve the same function as hair nets.

Some claim the cap is a potential carrier of bacteria and other disease-causing pathogens that could then be transmitted from patient to patient. However, such incidents can be prevented when infection control procedures are followed.