This study presents the development and basic psychometric characteristics of the "School Safety and Security Questionnaire" (SSSQ). This new measure was constructed to assess middle grade students' perceptions of safety and security during the school year. The content validity of the theoretically-based instrument was assessed and the measure was pilot tested and modified. Middle grade students (N=519) were then administered the SSSQ. The evidence presented here provides strong support for the preliminary reliability and validity of the measure. Internal consistency reliability (alpha) estimates and item-total correlations suggested good scale reliability. The factor structure, as determined through principle axis factor analysis, clearly reflected the anticipated conceptual structure. Three theoretically relevant factors were retained; areas of concern, threatening events, and existing supports. Factor loadings indicated that the individual items belonged to their respective domains, as hypothesized. The SSSQ provides a useful tool for assessing safety and security perceptions in the middle-grade environment. Gathering school-specific information offers school personnel base-line data useful in planning interventions and monitoring safety programs. (Contains 2 tables.)