There is a dearth of research examining school and district factors associated with the abandonment of evidence-based practice in schools. In this mixed-methods study, we surveyed 23 school personnel working with 30 schools that abandoned and then readopted school-wide positive behavioral interventions and supports (SWPBIS). Our aims were to identify critical features abandoned and perceived reasons for abandonment and readoption of SWPBIS practices. SWPBIS features most often abandoned included data-based decision making and school-wide acknowledgement systems. Lack of staff buy-in was the most commonly reported reason for abandonment, and a new school administrator was the most commonly reported reason for readoption. Implications for research and how schools could safeguard against abandonment of evidence-based practices are discussed. [This is the advance online version of a paper published in "Journal of Positive Behavior Interventions" (EJ1244498).]