Most economic research about self-protection against crime concentrates on self-protection by individuals, households, and stores - private economic agents. We know much less about self-protection in public economic settings, such as by schools; this article takes a step towards learning more. An economic agent who self-protects benefits by reducing vulnerability to crime but incurs self-protection costs whether a victimization occurs or not; should a crime occur, the agent further bears the cost of the victimization itself. The agent, a school administrator in this application, must determine the optimal level of self-protection within this environment. Empirical results obtained using data from the 2004 and 2006 School Survey on Crime and Safety (SSOCS) show that schools self-protect (use professional security personnel) much in line with theoretical predictions. Among other findings, schools located in larger cities and that have a larger and older student body self-protect more prevalently than other schools, while schools with more academically able students self-protect less than schools with less productive student inputs.