A cavalier hat is a type of hat with a wide brim that was popular in 17th-century Europe. These hats were often made of felt and usually decorated with an ostrich feather. They were often folded up on one side or had one side of the brim fastened to the crown of the hat (similar to the slouch hat), which was then decorated with feathers.

Cavalier hats get their name from the supporters of Charles I of England during the English Civil War, known as the Cavaliers, who stood out for their extravagant clothing. It was a common hat type throughout Europe during the 17th century, until it was later replaced in fashion by the tricorne, which was originally a cavalier hat with the brim tied into a triangle.
