A famine is a widespread shortage of food that may apply to any faunal species, which phenomenon is usually accompanied by regional malnutrition, starvation, epidemic, and increased mortality.

Presently many famines are caused simply by imbalance of food production compared to the large populations of countries whose population exceeds the regional carrying capacity. Historically, famines have occurred among the poor because of agricultural problems such as drought, crop failure, or pestilence. A famine can be made worse by war or economic policies which encumber food distribution. Epidemics can reduce available labor. Changing weather patterns, the ineffectiveness of medieval governments in dealing with crises, wars, and epidemic diseases like the Black Death helped to cause hundreds of famines in Europe during the Middle Ages, including 95 in Britain and 75 in France. In France, the Hundred Years' War, crop failures and epidemics reduced the population by two-thirds. Although most famines coincide with regional shortages of food, famine infrequently has occurred amid plenty or on account of acts of economic or military policy that have deprived certain populations of sufficient food to ensure survival.

During the 20th century, an estimated 70 million people died from famines across the world, of whom an estimated 30 million died during the famine of 1958–61 in China. The other most notable famines of the century included the 1942–1945 disaster in Bengal, famines in China in 1928 and 1942, and a sequence of famines in the Soviet Union, including the Holodomor, Stalin's famine inflicted on Ukraine in 1932–33. A few of the great famines of the late 20th century were: the Biafran famine in the 1960s, the disaster in Cambodia in the 1970s, the Ethiopian famine of 1983–85 and the North Korean famine of the 1990s.

Famine is a failure of the poor to command sufficient resources to acquire essential food (the "entitlement theory" of Amartya Sen). Understanding the causes of famine relies upon examining the political-economic processes, the reasons for mortality in famines, the extent to which famine-vulnerable communities have strategies for coping with the threat of famine, farmers being unable to escape debt without selling their farms, and the role of warfare and terrorism in creating famine. Modern relief agencies categorize various gradations of famine according to a famine scale.

Many areas that suffered famines in the past have protected themselves through technological and social development. The first area in Europe to eliminate famine was the Netherlands, which saw its last peacetime famines in the early 17th century as it became a major economic power and established a complex economic organization. Noting that many famines occur under dictatorship, colonial rule, or during war, Amartya Sen has posited that no functioning democracy has suffered a famine in modern times.