Gobstoppers, known as jawbreakers in Canada and the United States, are a type of hard confectionery. They are usually round, usually range from about 1 cm across to 3 cm across (though much bigger gobstoppers can sometimes be found in Canadian/US candy stores, some stores or stands in Europe and many theme parks, up to 8 cm in diameter) and are traditionally very hard.

The term gobstopper derives from 'gob', which is United Kingdom/Ireland slang for mouth.

Gobstoppers usually consist of a number of layers, each layer dissolving to reveal a different colored (and sometimes differently flavoured) layer, before dissolving completely. Gobstoppers are sucked or licked, being too hard to bite without risking dental damage (hence the US title).

Gobstoppers have been sold in traditional sweet shops for at least a century, often sold by weight from jars. As gobstoppers dissolve very slowly, they last a very long time in the mouth, which is a major factor in their enduring popularity with children. Larger ones can take days or even weeks to fully dissolve, risking a different kind of dental damage.

Gobstoppers are made by slowly depositing layers onto a core (such as a single sugar grain or anise seed). Gobstoppers are made in large, rotating, heated pans. The candies take several weeks to manufacture, as the process of adding liquid sugar is repeated multiple times (more than 100 times over two weeks to make a one inch ball). Colour and flavour are also added during the panning process.

In 2003, Taquandra Diggs, a nine year old girl in Starke, Florida, suffered severe burns, allegedly from biting down on a Wonka Everlasting Gobstopper that had been left out in the sun. Diggs and several other victims' families filed lawsuits against Nestlé for medical bills resulting from plastic surgery as well as pain and suffering; the matters were later settled outside of court for an undisclosed amount.

A 2004 episode of the Discovery Channel television program MythBusters episode subsection named Exploding Jawbreakers then demonstrated that heating a gobstopper in a microwave oven can cause the different layers inside to heat at different rates, yielding an explosive spray of very hot candy when compressed; MythBusters crew members Adam Savage and Christine Chamberlain received light burns after a gobstopper exploded.