A candy thermometer, also known as a sugar thermometer or jam thermometer, is a cooking thermometer used to measure the temperature and therefore the stage of a cooking sugar solution. It is similar to a meat thermometer but can read higher temperatures, usually 400 °F/200 °C or more. Candy thermometers can also be used to measure hot oil for deep frying. They have been used by the general public since World War I, although they had been available to professional candymakers earlier than that and were mentioned as early as 1896 in Fannie Farmers Boston Cooking-School Cook Book.

Types of candy thermometers include liquid thermometers, coil spring or "dial" thermometers that use a bimetallic strip, and digital thermometers, which are often more precise. They may include a clip to attach the thermometer to the side of the saucepan. Some thermometers have markers indicating which stage the sugar is at, and alarms that go off after a given temperature is reached.

Candy thermometers have a longer design, allowing them to safely soak in hot and boiling oil or sugar solutions. They can read up to 400 F (204 C), while most digital meat thermometers can only read up to 200 F (93 C) . Candy making generally requires the use of a thermometer, and candy thermometers are readily available in houseware stores and almost every supermarket in the states.