The Westchester Library System (WLS) is a state- chartered, cooperative library system serving all 38 Westchester member public libraries and the county's citizens. As one of the 23 public library systems serving New York State's public libraries, the Westchester Library System was established in 1958.

The mission of the Westchester Library System is to enhance and improve the County's libraries, and to ensure that all residents have excellent library service regardless of their location.