The purpose of this quantitative correlational research was to examine if and to what extent principal support of school climate related to student weapons and student aggression incidents in a southwest school district. Three theoretical foundations supported this research: Socio-ecological theory, Social Learning Theory, and School Climate Framework. Two research questions asked about the correlations of principal support of school climate with student weapons and student aggression incidents on school campuses. The study was conducted with archival data from the 2018-2019 Clark County School District Districtwide Survey, initially collected for the 2018-2019 Clark County School District Accountability Report, and stored on the Nevada Department of Education Report Card website. The datasets analyzed in this study included staff participants' responses from 314 schools. The results of nonparametric Spearman's correlation analyses showed statistically significant inverse correlations of principal support of school climate with student aggression incidents (r[subscript s] = -0.353, p < 0.001) and student weapons incidents (r[subscript s] = -0.386, p < 0.001). These results justify further research in different school districts and different states. If confirmed by future studies, these findings may be used to create professional development for school principals aimed at strengthening their support of school climate for the purpose of curbing student aggression and student weapons incidents on school campuses. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]