A BSTRACT Background: Unhealthy food consumption and physical inactivity in adolescents play a key role in the development of non-communicable diseases (NCDs). Objectives: The study was planned to capture the reasons and solutions for unhealthy food consumption and physical inactivity among school-going adolescents. Methods: A school-based sequential mixed-methods study was conducted in Puducherry for six months. In Phase I, a survey (QUAN) was carried out among 405 representative students from 9 th to 12 th standards to identify the reasons for unhealthy behaviors. Then, Phase II compromised two focus group discussions (FGDs) (QUAL) with 20 purposively selected school staff, parents, and healthcare professionals to explore the solutions for unhealthy behaviors. In Phase III, the key action points were ranked (QUAL) by 60 teachers. Quantitative data was analyzed in Epi_Info 7.1.5.0 software (Centers for Disease Control and Prevention; Atlanta, Georgia, US). Thematic content analysis was done for the qualitative data in Atlas.ti.9 software (Scientific Software Development GmbH, Berlin). Further, mean rank and Kendall’s concordance coefficient (W) were calculated for the ranked data in SPSS 24 software (SPSS Inc; Chicago, Illinois, USA). Results: About 70.1% of students had unhealthy food consumption and 61% of students lacked physical activity. Notably, 59.9% of males preferred unhealthy foods, and 65.2% of females were physically inactive. The leading reasons for unhealthy eating habits were taste (78.9%), increased online food delivery (75.7%), and attractive advertisements (74.3%). Whereas, the prime reasons for sedentary behaviors were increased study load (81.8%), high-density traffic (74.9%), and insufficient recreational facilities (71.7%). Conclusion: The prioritized feasible action points would help in the development of context-specific behavior change communication strategies for future health promotion interventions in resource-poor settings.