The Sims 3: Late Night (LN) is the third expansion pack for the strategic life simulation computer game The Sims 3 and is similar to previous expansions The Sims 2: Nightlife for The Sims 2 and The Sims: Hot Date for The Sims. It incorporates some elements from The Sims: House Party, The Sims: Superstar, and The Urbz: Sims in the City.

This expansion pack also introduces a brand new city neighborhood named 'Bridgeport', based on the cities of San Francisco and Los Angeles, which is divided into an urban/downtown area, a less dense uptown area, and a hilly, affluent suburb.