A mental and behavioral illness is described as a clinically significant illness with changes in thought, emotion, or behavior related to a personal situation.

Objectives of the study: To assess the knowledge regarding mental health & illness and level of stress. 2. To determine the effectiveness of Educational Intervention on knowledge regarding mental health & illness and level of stress 3. To find out the association between pre-test knowledge level on mental health & illness and selected demographic variables. 4. To find out the association between pre-test stress level and selected demographic variables. 5. To find out relation between knowledge score of mental health & Illness with stress level.

Methodology: Quantitative research approach with pre-experimental research design was used.

Sampling: 300 samples was chosen with consecutive sampling technique.

Result: In pretest mean score for knowledge and stress were 8.9 and 27.9 respectively and post-test were 19.7 and 17.45 which showed that education intervention improve the knowledge and decrease stress among adolescent. Improved knowledge reduces stress level.

Conclusion: educational intervention improve knowledge level which significantly reduce level of stress.