This document provides a timeline and overview of the history of school psychology from 1900 to the present. It describes two major periods: the "Hybrid Years" from 1890-1969 when school psychology blended assessment and other practices to support special education placement, and the "Thoroughbred Years" from 1970 onward marked by growth in training programs, practitioners, and professional standards. Key events included the first training program in 1925, formation of the APA and AAAP in the 1930s, passage of federal special education law in 1975, and establishment of national certification in the 1980s. The role of school psychologists has evolved from a focus on assessment and placement to include prevention and intervention services.