This work examines the effects of Socially Maladjusted Behavior (SMB) on the academic performance of learners in selected public primary schools in Kasarani Sub-county of Nairobi County, Kenya. The study adopts a psycho-social development theory, which combines psychological and sociological views to account for the personal and social maladjustment problems typical of human behavior, to account for the effects of socially maladjusted behavior among primary school learners. It aims at investigating the main causes and effects of socially maladjusted behavior among primary school learners and also evaluates the various intervention strategies used by teachers to assist learners who exhibit this behavior. It observes that socially maladjusted behavior is a rampant phenomenon among school going children in the sampled schools, and is often characterized by cheating, truancy, delinquent behavior and rebellion against established school rules. The study recommends several intervention strategies, which, if well employed, would mitigate the effects of socially maladjusted behavior on the academic performance of learners, thereby having a positive impact on the learning process. ukryj opis