The Los Angeles Public Library system (LAPL) is a public library system in Los Angeles, California. The system holds more than six million volumes, and with around 19 million residents in the Greater Los Angeles area, it serves the largest metropolitan population of any public library system in the United States. The system is overseen by a Board of Library Commissioners with five members appointed by the mayor of Los Angeles in staggered terms, and operates 72 library branches throughout the city. In 1997 a local historian described it as "one of the biggest and best-regarded library systems in the nation." It is not to be confused with the LA County Library system which operates several library branches across certain areas of Los Angeles County.

LA County Library is one of the largest public library systems in the United States which serves residents living in 49 of the 88 incorporated cities of Los Angeles County, California. United States, and those living in unincorporated areas resulting in a service area extending over 3,000 square miles (7,800 km2). The LA County Library system provides local libraries to several unincorporated areas and cities across Los Angeles County, and is not to be confused with the Los Angeles Public Library (LAPL) system, which serves areas within the city of Los Angeles.