Dansk Plakatmuseum (The Danish Poster Museum) is Denmark's only museum dedicated solely to posters and placards, located in the open-air museum Den Gamle By in Aarhus. It showcases a broad historical and artistic range of poster art, combining design, communication, and everyday culture from the late 19th century onward.

The museum holds a collection of around 400,000 posters from more than 120 countries, including political, cultural, artistic, commercial, and informational posters as well as newspaper menu-cards. It is regarded as a unique "museum within a museum" inside Den Gamle By, which recreates urban life in the 1970s.