Lyndon is a 4th-class city in Jefferson County, Kentucky, in the United States. The population was 9,369 at the time of the year 2000 U.S. census.

Incorporated on May 10, 1965, Lyndon became part of the new Louisville Metro government in 2003. It remains an independent city with its own mayor and emergency services and is not counted in Louisville's population although its citizens can vote for the mayor of Louisville and Metro Council members.