Literature on problematic absenteeism in children and adolescents is diverse and dispersed across multiple disciplines, as it has long been a multifaceted and vexatious concern for psychologists, educators, and researchers (Kearney & Bates, 2005). Unfortunately, the investigation of problematic absenteeism from such diverse perspectives over numerous decades has resulted in considerable disparity among researchers and practitioners with regard to the terminology, classification, assessment, and treatment of youth school refusers, as well as poor comparability across publications (Kearney, 2003). Thus, to build consensus and remedy the disparity in terminology to describe children and adolescents with problematic absenteeism the umbrella term school refusal behavior is used (Kearney & Silverman, 1993). Overall prevalence of school refusal behavior in children and adolescents is an undeniable concern for school personnel, as it is exhibited in approximately 28% to 35% of youths (Kearney, 2001; Kearney, 2018; Kearney & Bates, 2005; Pina et al., 2009). The purpose of this study was to examine school psychologists' knowledge of school refusal behavior in children and adolescents as it pertains to symptoms, comorbid psychiatric disorders, the functional model, assessment, and treatment. Additionally, this study investigated the disparity of knowledge among school psychologists to determine the need for professional development. Participants included 32 practicing school psychologists who were randomly selected from California school district directories. Results indicated that overall, school psychologists maintained minimal to moderate knowledge of school refusal behavior. Based on these findings, school psychologists should receive professional development in the area of school refusal behavior. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]