This article argues that metal detectors bestow an organizational stigma to schools. One symptom of this is students' heightened level of fear at school. Using data from the National Longitudinal Study of Adolescent Health (Add Health) and a matched-pair design, this study finds that metal detectors are negatively correlated with students' sense of safety at school, net of the level of violence at school. However, this association is different for urban students. The negative association between metal detectors and urban students' sense of safety is 13% less than what it is for students attending suburban or rural schools. (Contains 2 tables.)