School security measures have become commonplace in recent years. Still, little quantitative research has examined how this trend shapes students' perceptions of school. This study examines how students' exposure to school security relates to their sense of school connectedness, with particular attention to the difference between white and nonwhite students. Using a longitudinal sample of 359 students across eight high schools in one urban school district, this study uses student fixed-effects models to link changes in students' exposure to security and connectedness with teachers, peers, and the school. Increases in students' exposure to security were associated with small decreases in students' connectedness to peers, and this association differed for white and nonwhite students. There was no significant association between exposure to security and connectedness with teachers or the school. Increased exposure to school security has limited consequences for within-person changes in school connectedness; however, between-person differences may still exist.