The childhood period is vital because of socialization process by the transmission of attitude, customs and behavior through the influences of the family and community. They need appropriate care for survival and healthy development. Better nutrition, education and family planning are essential aspects of child health. In education, technology helps to enhanced learning, foster skills and critical thinking². Technology is the application of scientific knowledge to the practical aims of human life. There are different types of technology like computer, mobile phones, laptops, digital watches etc. among advanced technology devices; a mobile phone is a prominent example.

Materials and Methodology: The main objectives of this study were to evaluate the effectiveness of health teaching programme on knowledge regarding effect of mobile phone use on psychosocial development in children among school children. Quantitative research approach was used for this study. The study was carried out in selected High School in Kakching. The research design was pre-experimental one group pre- test & post-test research design. The sample comprised of 50 High School Children. The school children were selected by purposive sampling technique. The data collection was done between 3-11-2025 to 10-11-2025. Formal written permission was obtained from the authorities to conduct the study. Data was collected by administering a self-administered knowledge questionnaire. The data was analyzed by using descriptive and inferential statistics.

Major findings and Results: The results of the study shown that pre-test level of knowledge were30(60%) High School Children had inadequate knowledge, followed by 20(40%) had moderate knowledge and after intervention results of the study shown that post-test level of knowledge was 44(88%) High School Children have moderate knowledge, followed by 06 (12%) had adequate knowledge. The overall mean knowledge score of pre-tests was 13.54andpost-testwas 19.64andmean difference was 6.1. The obtained ‘t’ value 12.063 is greater than the tablevalueat0. 05levelofsignificance.It shows that there was significance difference between pre-test and the post-test knowledge score of High School Children regarding effect of mobile phone use on psychosocial development. The significant association between the post-test level of knowledge of High School Children regarding effect of mobile phone use on psychosocial development with selected socio-demographic variable such as age(x²=3.977), gender(x²=0.440), religion (x²=2.581), type of residence (x²=3.209), type of family(x²=0.006), family income (x²=4.086), educational status (x²=constant), uses of smart phone (x²=1.497), knowledge regarding using smart phone (x²=2.153), reason for using smart phone (x²=2.153), hour spent on mobile phone use (x²=4.832). Thus, it can be interpreted that there is no significant association between the post-test level of knowledge with the selected socio-demographic variables at p<0.05 level of significance.