The Batería III Woodcock-Muñoz (Batería III) (Muñoz-Sandoval, Woodcock, McGrew, & Mather, 2005a) is the Spanish version of the Woodcock-Johnson® III (WJ III®) (Woodcock, McGrew, & Mather, 2001). All of the Batería III test materials are in Spanish, including the Examiner’s Manuals and the Technical Manual. This Overview and Technical Supplement is written in English. It includes an overview of the Batería III tests and clusters. Examiner qualification guidelines are outlined and some unique interpretation features are discussed. Information about the development of the Batería III, including supplementary reliability and validity information based on the Spanish calibration data, is provided. (author abstract)