Lepton pl. Lepta (Λεπτόν pl. Λεπτά)) is the name of various fractional units of currency used in the Greek-speaking world from antiquity until today.

The word means "small" or "thin", and during classical and hellenistic times a lepton was always a small value coin, usually the smallest available denomination of another currency. The Roman mite was informally called lepton in the Greek-speaking parts of the Roman Empire; this use is seen in the New Testament.

In modern Greece, lepton (modern form: lepto, Λεπτό) is the name of the 1/100 denomination of all the official currencies of the Greek state: The Phoenix (1827-1832), the Drachma (1832-2001) and the Euro (2002-current). Its unofficial currency sign is Λ.