Objective: To determine the relationship between self-esteem and aggressiveness of students in the sixth cycle of regular basic education in the city of Puerto Maldonado, Peru. Materials and methods: The research had a quantitative approach; the design was non-experimental and the descriptive type-transectional correlational. The sample consisted of 226 students who were in the sixth cycle of regular basic education in an educational institution in the city of Puerto Maldonado, to whom the Self-Esteem Test for Schoolchildren and the Aggression Questionnaire was applied, instruments with adequate levels of reliability and validity. Subsequently, the responses were systematized and analyzed using the SPSS® program, version 23. Results: It was found that the students were characterized by moderate levels of self-esteem (44.7%) and aggressiveness (48.2%). Likewise, it was determined that self-esteem is inversely and significantly related to aggressiveness. Spearman’s rho correlation coefficient was-0.762 with a p-value lower than the significance level (p <0.05). Conclusions: It is necessary to apply psychoeducational programs that allow students to develop self-esteem and reduce levels of aggressiveness. In this way, protective factors will be created in students and fostering a healthy school climate.