The study determines how aggression or aggressive behavior of Mindanao State University STC-SHS students are related to academic performance in school specifically those who belong to the middle socio-economic status and those who are Maranaos and visayan speaking. The study found out the following: mestizos - high level Tausugs - low level female - high and with better academic performance male - moderate or low level of aggression and with unsatisfactory academic performance. Sex and ethnicity proved to be significantly related to aggression and academic performance.