Grade I listed buildings in Lancashire

This is a list of Grade I listed buildings in Lancashire, England.

In the United Kingdom, the term "listed building" refers to a building or other structure officially designated as being of special architectural, historical or cultural significance. These buildings are in three grades: Grade I consists of buildings of outstanding architectural or historical interest. Buildings in England are listed by the Secretary of State for Culture, Media and Sport on recommendations provided by English Heritage, which also determines the grading.