"Pop! Goes the Weasel" is a traditional English and American song, a country dance, nursery rhyme, and singing game that emerged in the mid-19th century. It is commonly used in jack-in-the-box toys and for ice cream trucks.

A jack-in-the-box is a children's toy that outwardly consists of a music box with a crank. When the crank is turned, a music box mechanism in the toy plays a melody. After the crank has been turned a sufficient number of times, the lid pops open and a figure, usually a clown or jester, pops out of the box. Some jacks-in-the-box open at random times when cranked, making the startle even more effective. Many of those that use "Pop Goes the Weasel" open at the point in the melody when the word "pop" would be sung. In 2005, the jack-in-the-box was inducted into the U.S. National Toy Hall of Fame, where are displayed all types of versions of the toy, starting from the beginning versions, and ending with the most recently manufactured versions.