The Third Hellenic Republic is the period in modern Greek history that stretches from 1974, with the fall of the Greek military junta and the final abolition of the Greek monarchy, to the present day.

It is considered the third period of republican rule in Greece, following the First Republic during the Greek War of Independence (1821–1832) and the Second Republic during the temporary abolition of the monarchy in 1924–1935.

The term "Metapolitefsi" is commonly used for the entire period, but this term is properly restricted to the early part of the period, beginning with the fall of the junta and culminating in the democratic transformation of the country. While the First and Second Hellenic Republics are not in common use except in a historiographic context, the term Third Hellenic Republic is used frequently.

The Third Hellenic Republic has been characterised by the development of social freedoms, the European orientation of Greece and the political dominance of the parties ND and PASOK. On the negative side the period has included high corruption, deterioration of certain economic indexes such as public debt, and nepotism, mostly in the political scene and the state offices.