Background: This study aimed to establish the effectiveness of a hypertension knowledge education intervention among Indian adolescents to foster lifestyle changes aimed at preventing hypertension. Methods: The Hypertension Knowledge Test (HKT) was used to assess changes in knowledge using a repeated-measures one-way analysis of variance (ANOVA). The Healthy Lifestyle Practice Scale for Children and Adolescents (HELIPSCA) indexed healthy lifestyle practices, with paired t-tests used to compare pre- and post-intervention scores. A two-way mixed ANOVA examined changes in healthy lifestyle practices among adolescents divided in terms of early and late stage of development. Results: Significant mean differences were observed in overall hypertension knowledge across four domains: general awareness, lifestyle factors, causes and care, and medication management and across time periods. There was a significant improvement in HELIPSCA scores post-intervention, particularly among early adolescents. Conclusion: The hypertension knowledge intervention examined in this study was effective in establishing a cognitive base among school children, with knowledge retention observed for 3 months. Moreover, this knowledge increase was associated with a parallel change in improved healthy lifestyle practices, notably among early adolescents. These findings underscore the importance of providing school-based education programmes early in adolescence to promote awareness of chronic illnesses and encourage healthy lifestyle choices.