A pin-up girl, also known as a pin-up model, is a model whose mass-produced pictures see wide appeal as popular culture. Pin-ups are intended for informal display, e.g. meant to be "pinned-up" on a wall. Pin-up girls may be glamour models, fashion models, or actresses.
Many pin-ups were photographs of celebrities who were considered sex symbols. One of the most popular early pin-up girls was Betty Grable, whose poster was ubiquitous in the lockers of G.I.s during World War II. Other pin-ups were artwork, often depicting idealized versions of what some thought a particularly beautiful or attractive woman should look like.