The data revealed that 25 percent of the students carried a weapon to school in the last year. Self-defense was the most commonly reported reason for in-school weapon carrying. Results from a simultaneous logistic regression analysis indicated increased risk of in-school weapon carrying among students who were male, who were affiliated with gangs or tagging crews, who were exposed to peers who carried weapons to school, and who felt vulnerable to being victimized. Findings indicated that prevention programs targeted at reducing in-school weapon carrying may benefit from a comprehensive focus that includes efforts to reduce involvement in other problem behaviors, influence norms regarding weapon carrying, and reduce actual and perceived vulnerability to victimization. Tables and 29 references (Author abstract modified)