The LA County Regional Planning Commission acts as an advisory body to the County Board of Supervisors on all planning matters. They administer provisions of the State Planning Law (Title 7, Division I, of the Government Code), the State Subdivision Map Act, California Environmental Quality Act, and the LA County ordinances affecting planning such as the County Zoning Ordinance and Subdivision Ordinance. They advise on planning policies and conduct regular public hearings and meetings on Wednesdays.

RPC consists of five Commissioners. They are appointed to four-year terms by the County Board of Supervisors. There are also four advisory non-voting members: the Forester and Fire Warden, Director of Public Works, Superintendent of Parks and Recreation, and Agricultural Commissioner.