From Colorado and Connecticut to Florida, school shootings have struck the U.S. education system, accelerating and deepening the fortification of schools. Fortification entails prioritizing and instituting multiple types of infrastructure, technology, and routines that militarize schools while defining 'safety' as a function of the building and framing educators as responders to gun violence. The school security industry is now a $2.7 billion market, so it is vital to comprehend the structures, policies, conceptualizations, resources, and activities linked with school safety. We apply structure-agency theory to advance arguments on the fortification of schools. In particular, we explain the interrelation between racialized school safety policies and practices. Thus, we highlight educators’ discretion in enacting safety policy in varied contexts. Our discussion of fortification sheds light on the nexus of guns and schools, operationalizes facets of structure-agency theory, and provides recommendations for research and practice.