A Chianti wine (, also US: , Italian: [ˈkjanti]) is any wine produced in the Chianti region of central Tuscany. It was historically associated with a squat bottle enclosed in a straw basket, called a fiasco ("flask"; pl. fiaschi). However, the fiasco is only used by a few makers of the wine as most Chianti is now bottled in more standard shaped wine bottles. In the mid-late 19th century, Baron Bettino Ricasoli (later Prime Minister of the Kingdom of Italy) helped establish Sangiovese as the blend's dominant grape variety, creating the blueprint for today's Chianti wines.

The first definition of a wine area called Chianti was made in 1716. It described the area near the villages of Gaiole, Castellina and Radda; the so-called Lega del Chianti and later Provincia del Chianti (Chianti province). In 1932 the Chianti area was completely redrawn and divided into seven sub-areas: Classico, Colli Aretini, Colli Fiorentini, Colline Pisane, Colli Senesi, Montalbano and Rùfina. Most of the villages that in 1932 were added to the newly defined Chianti Classico region added in Chianti to their names, for example Greve in Chianti, which amended its name in 1972. Wines labelled Chianti Classico come from the largest sub-area of Chianti, which includes the original Chianti heartland. Only Chianti from this sub-zone may display the black rooster (gallo nero) seal on the neck of the bottle, which indicates that the producer of the wine is a member of the Chianti Classico Consortium, the local association of producers. Other variants, with the exception of Rufina north-east of Florence and Montalbano south of Pistoia, originate in the named provinces: Siena for the Colli Senesi, Florence for the Colli Fiorentini, Arezzo for the Colli Aretini and Pisa for the Colline Pisane. In 1996 part of the Colli Fiorentini sub-area was renamed Montespertoli.

During the 1970s producers started to reduce the quantity of white grapes in Chianti. In 1995 it became legal to produce a Chianti with 100% Sangiovese. For a wine to retain the name of Chianti it must be produced with at least 80% Sangiovese grapes. Aged Chianti (38 months instead of 4–7) may be labelled as Riserva. Chianti that meets more stringent requirements (lower yield, higher alcohol content and dry extract) may be labelled as Chianti Superiore, although Chianti from the Classico sub-area is not allowed in any event to be labelled as Superiore.