BACKGROUND: Behavioural disorders of children lead to abnormality in their Personality, emotions or behavior, which is dangerous and affect to him/her, family and society. Behavioural disorders are caused by multiple factors like faulty parental attitude, inadequate family environment (broken families, low socio-economic status, lack of love and affection), mentally and physically sick or handicapped, influence of social relationship, influence of mass media, and influence of social change. Some children show symptoms that are consistent with diagnoses of Oppositional Defiant Disorder (ODD), Attention-Deficit hyperactivity Disorder (ADHD), and Learning disability. Objective: The aim of the study was to assess the effectiveness of planned teaching program on behavioural disorders among primary school teachers at Dadra & Nagar Haveli, Silvassa. Methodology: A pre-experimental one group pre-test post-test research design was adopted, through non probability purposive sampling technique, 150 samples were selected from selected primary school of Dadra and Nagar Haveli, Silvassa. Demographic Variables based on baseline Performa was used to collect demographic data and Self-administered knowledge questionnaire were used to assess the existing knowledge level of primary school teachers regarding behavioural disorder in school aged children. Planned teaching program on behavioral disorders in children was administered to primary school teachers to enhance the knowledge followed by post was conducted after 7 days. The data was analyzed and interpreted based on descriptive and inferential statistics. Result: The result of the study shows that, the overall post-test knowledge mean percentage (71.26%) is greater than pretest knowledge mean percentage (39.57%). The calculated “t” value (27.174) of the knowledge score of the primary school teachers regarding behavioural disorders of school aged children is greater than the table value at 0.05 level of significance hence the planned teaching programme is effective to improve the knowledge of school teachers. Conclusion: Thus, it can be concluded that Planned teaching programme was effective in improving the knowledge of primary school teacher regarding behavioural disorders in school aged children. Key words: Assess, Effectiveness, Knowledge of primary school teachers, Behavioural disorders, School aged children, planned teaching program.