This study was done to find out the extent of influence of certain factors on the aggressive behavior of Grades Five and Six pupils. Specifically, it sought to find out the aggressive behavior tendencies of the pupils, the level of influence of the home, peers, and school factors, and the significant difference in the influence of the home, peer, and school factors when schoolaged children are grouped as uncontrolled, assertive/aggressive, or both. The instruments used in this study were the researcher-made Pupils’ Survey Questionnaire and a Standardized Test, the Children Personality Questionnaire or CPQ. Using the frequency count, mean, t test, and Analysis of Variance as statistical tools, it is found that the aggressive behavior tendencies of pupils revealed two factors: Factor Q3 (uncontrolled type of behavior) and the Factor E (assertive/aggressive type of behavior), respectively. Pupils with low score in factor Q3 are those who have uncontrolled behavior tendencies, while high scores in factor E are pupils who have assertive/aggressive behavior tendencies. There were 18 pupils whose aggressive behavior tendencies fell under the uncontrolled category; eight in the assertive/aggressive category, and three pupils exhibited both uncontrolled and assertive/aggressive behavior tendencies. The level of influence on the aggressive behavior tendencies is moderate for the home and school factors and low for peer factors. The influence of home factors do not differ significantly when grouped as uncontrolled, assertive/aggressive, or both. However, the influence of School Factors, which are the classroom management styles namely, authoritative, permissive, and authoritarian, differed significantly on the aggressive behavior of the pupils, specifically the authoritarian classroom management style. Moreover, the influence of classroom atmosphere does not differ significantly on the aggressive behavior tendencies of the pupils.