It is named for Naupaktos (Ναύπακτος, Latinized as Naupactus), an important Athenian naval station in the Peloponnesian war.

As a strategically crucial possession controlling access to the Gulf of Corinth, Naupaktos changed hands many times during the Crusades and the Ottoman–Venetian Wars.

The Greek National Road 48/E65 (Antirrio – Nafpaktos – Delphi – Livadeia) passes north of the town.

The ancient name Naupaktos (Ναύπακτος) means "boatyard" (from ναύς naus "ship" and πήγ- pêg- "to fix, fasten").

By the late medieval period, the local name had evolved into Nepahtos (Νέπαχτος), Epaktos or Epahtos (Έπακτος, Έπαχτος).

In Classical Antiquity, it was an important town of the Locri Ozolae and the best harbour on the northern coast of the Corinthian Gulf.

[6][7][8] Though Naupactus was indebted for its historical importance to its harbour at the entrance of the Corinthian gulf, it was probably originally chosen as a site for a city on account of its strong hill, fertile plains, and copious supply of running water.

[20] The Roman playwright Plautus mentions Naupactus in his comedy Miles Gloriosus as the destination of an Athenian master (Pleusicles) who is on a diplomatic mission to the city.

[25][27] Under its metropolitan, John Apokaukos, the see of Naupactus gained in importance and headed the local synod for the southern half of the Epirote domains.

It was briefly occupied Knights Hospitaller in 1378, and, now wedged between the expanding lands of the Count of Cephalonia Carlo I Tocco and the Ottoman possessions, sold to the Republic of Venice by Paul Spata in 1407.

Among those who fought in the Battle of Lepanto was Miguel de Cervantes, the most famous Spanish writer; there is a statue located at the port, in his honour.

The metropolitan see of Naupactus depended on the pope of Rome until 733, when Leo III the Isaurian annexed it to the Patriarchate of Constantinople.

[35] The zealous youth St. Nicholas of Trani after a failed attempt at the mortifications of cenobitic life at the Hosios Loukas monastery in Boetia set sail in the spring of 1094 on a pilgrimage to Rome for the Solemnity of Sts.

His pious habit of evangelizing the sailors with constant proclamations (in Greek kerygma from κηρύσσω, meaning "to cry or proclaim as a herald") of the phrase Kyrie Eleison according to legend, led them to throw him overboard.

Miraculous cures led to him being publicly acclaimed as worthy of veneration by the Bishop of Trani at the Council of Bari in 1098.

The bypass has contributed significantly in lowering the number of heavy trucks passing through the narrow streets of the town.