The Northwest Multiple Listing Service (NWMLS) is a member-owned, not-for-profit organization that facilitates cooperation among its member real estate firms. The organization was formed when four innovative multiple listing services joined forces to streamline services for their clients. The organization revolutionized the industry by centralizing real estate listing data and being the first MLS in the country to put this data online. 

Originally called the Puget Sound Multiple Listing Association, the name changed in 1996 to Northwest Multiple Listing Service to reflect the growing geographic area served. Today, NWMLS is one of the leading multiple listing services in the country, providing services to more than 30,000+ real estate brokers across Washington state.