Mutton is meat which is harvested from a mature sheep, so it tends to be tough, with a more complex flavor than lamb, meat from younger sheep. Many parts of the world use mutton in their cuisine extensively; the Middle East, for example, is home to many famous mutton recipes. In other regions, consumers tend to prefer lamb, so mutton can be challenging to obtain. In the United States, for example, mutton is extremely rare, and consumers may need to track down a boutique butcher to obtain mutton.

Generally, mutton comes from a sheep which is over two years of age. The sheep may be male or female, although mutton from rams can be extremely gamy due to their hormonal balance. The meat is tougher because the animal is older, but it also has a more developed flavor. Since mutton is so tough, it needs to be cooked carefully; it benefits from long, slow simmering which will make the mutton extremely tender while bringing out the flavor.

Lamb, on the other hand, comes from a sheep which is less than one year old. In many countries, the bulk of the available lamb on the market is from sheep under six months of age. Because the animal is so young, lamb is extremely tender, and it can be prepared in a wide range of ways; lamb often tastes better rare, however. Many people who express distaste for lamb have experienced overcooked lamb which tends to be bland, dry, and chewy.

In some countries, meat from sheep between one and two years of age is called hoggett. Because these sheep are of an intermediate age, hoggett is not as tender as lamb, but not as tough as mutton, either. Some recipes call specifically for hoggett, while other cooks may prefer it because it mixes a bit of the best of both meats.

Mutton is an efficient food, because it takes advantage of the myriad uses of sheep. A sheep used for mutton may first be used for wool and milk, or to produce lambs to strengthen the herd. As sheep age and become less economically valuable, they can be converted to mutton.

Mutton stew or curry is a common mutton dish. Since stews and curries lend themselves well to slow cooking, mutton is an ideal meat for them. Mutton may also be roasted, although the roasting needs to be performed at a low temperature to keep the meat tender as it cooks. Many Indian dishes feature mutton, because beef is not eaten in most of India. Mutton pairs particularly well with the heavy spices used in a great deal of Indian cuisine, and it can be roosted in tandoori ovens, slowly simmered in curries, or even fried in some dishes.