Adolescents, with developing age, undergo certain developmental crises and encounter with “identity v/s role confusion, where a sense of endurance and uniformity develops from one’s perspective as well as other’s perspective for themselves, nonetheless it is a lifelong process, which extends beyond the years of adolescence. This is a critical period for development of self-esteem; however, tends to decline endangering the emotion regulation. Self-esteem being an integral aspect of the development includes personal beliefs about their skills, abilities, and social relationships, with momentary emotional states. Researchers have identified association of low self-esteem with stress, depressive symptoms. The purpose of the study was to see the effectiveness of Mindfulness and Assertiveness Training for self-esteem and stress among adolescents. A total sample of 10 adolescents aged between 15 to 18 were selected for the combined Mindfulness and Assertive therapy. The measures used to collect the data were Rosenberg Self-Esteem Scale, Perceived Stress Scale. The results calculated using non-parametric statistics on SPSS v25depicted significant difference in pre- and post-intervention at p-value α≤ 0.05. The effect size for all the constructs ranged from59-62% suggesting moderate effect size. Mindfulness and Assertiveness decreases quarrelsome behaviour enhancing agreeable behaviours, resulting in balanced state of self- esteem and emotions. Mindfulness with Assertive therapy is an effective approach for self-esteem issues which is an integral part of psycho-social development among adolescents and stress. However, there is an immense need for more intervention studies to be widely done to take care of the issues faced by the adolescents.