This study investigated the effectiveness of intervention among substance abuse higher secondary school students in relation topersonality and mental health. The sample consisted of 130 substance abuse higher secondary school students in Government and Aided schools in Kottayam district. The findings of the study revealed that there will be significant relationship between big five personality dimensions in relation to mental health in pre and post intervention. There will be significant difference in substance abuse (alcohol and drug involvement) among higher secondary school students with respect to certain selected socio demographic variables. The intervention is positively affect the overall mental health of the higher secondary school students. The results are discussed, the implications, recommendations and suggestions for further research are also given.