This study investigates how barriers to school-based crime prevention programming moderate the effects of situational crime prevention (SCP) policies on levels of violent crime in U.S. public high schools. Using data from the 2008 School Survey on Crime and Safety, we estimate a series of negative binomial regression models with interactions to investigate whether the effects of SCP policies on violent crime vary by the presence of school-based barriers to crime prevention, such as poor teacher training, inadequate funds, and lack of parental support. Our results indicate that the effect of certain SCP policies operate differently depending on the presence or absence of specific limiting factors. Policy implications of this research suggest that schools can aid in preventing violent crime by addressing obstacles to the effective implementation of school crime prevention efforts.