Lillebonne (French pronunciation: [lilbɔn]) is a commune in the Seine-Maritime department in the Normandy region in Northern France.

The important Lillebonne mosaic, well preserved and depicting a deer hunt, comes from a suburban villa and is on display at the Rouen Museum.

It was again ruined in the barbarian invasions of 273 after which the theatre was made into a fortress: the exits were blocked, wells were dug, and baths put up in the arena.

The church of Notre Dame, partly modern, preserves a Gothic portal of the 16th century, and a graceful tower of the same period.

Petrochemistry is now the main industry in the area, with a part of the nearby Notre-Dame-de-Gravenchon refining and petrochemical complex extending over the Lillebonne commune.