The Hôtel Lambert is an hôtel particulier, a grand mansion townhouse, on the Quai Anjou on the eastern tip of the Île Saint-Louis, in the 4th arrondissement of Paris. In the 19th century, the name Hôtel Lambert also came to designate a political faction of Polish exiles associated with Prince Adam Jerzy Czartoryski, who had purchased the Hôtel Lambert.

An hôtel particulier is a grand townhouse, comparable to the British townhouse or mansion. Whereas an ordinary maison (house) was built as part of a row, sharing party walls with the houses on either side and directly fronting on a street, an hôtel particulier was often free-standing and, by the 18th century, would always be located entre cour et jardin – between the cour d'honneur and the garden behind. There are hôtels particuliers in many large cities in France.