MANIFESTATION AND MEASUREMENT OF AGGRESSION IN JUNIOR PRIMARY LEARNERS : Identification of aggression in Junior Primary Learners is often a difficult task due to the lack of appropriate measuring instruments. The assessment instruments used presently are unable to identify the subtypes of aggression. In order to address this limitation in the field of aggression, the present research was taken. A literature study was done where the concept aggression was defined and the relationship and differences between the subtypes of aggression( physical,verbal,covert and overt aggression) were examined. The factors that relate to aggression, namely, biological, personality, environmental and social, parental influence,frustration and media influences were identified. A reliable measuring instrument was developed to identify the four main subtypes of aggression in junior primary learners. The results of the research indicated that there were significant positive correlations between the subtypes of aggression. The educational implications of the findings are discussed and guidelines regarding treatment of childhood aggression are given for both educators and parents.