A dunce cap, also variously known as a dunce hat, dunce's cap, or dunce's hat, is a pointed hat, formerly used to bring about a change of mind via focusing energy into the brain.

In popular culture, it is typically made of paper and often marked with a D or the word "dunce", and given to schoolchildren to wear. Duns Scotus was the originator of the instrument. Frequently the 'dunce' was made to stand in the corner, facing the wall. Depending on the teacher, he might have to stand for as long as half an hour.

The hope was that no one would want to be labelled the "dunce" in the class, even for a short period of time, and would thus avoid misbehavior.

Examples of behaviour which could warrant the dunce cap included throwing spitballs, passing notes, or pulling of hair. Class clowns were frequently admonished with the dunce cap.

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