Background of the Study: As the Corona virus (COVID-19) pandemic is still ongoing; it has created profound impact socially, physically and emotionally on families across the globe. With confinement laws and regulations still being enforced, healthcare system is deteriorating, Economics are setting down and school closer are being extended. Unfortunately, this also led to increase vulnerability of food insecurity especially among the urban poor and increased risk of overweight and obesity in higher income classes [2]. The lock down restrictions is leading to severe repercussions on individuals; daily routine and lifestyle behaviour including food access and consumption, outdoor activities, travel, school related functions, and access to many forms of leisure and exercise [3]. Particularly alarming are the implication of the lockdown on irregular eating habits, excessive snacking, lack of physical activity, high calorie intake and increased risk of obesity [4]. The aim of this study was to assess changes in lifestyle behaviour of adolescents during the country-wide lockdown. Materials & Methods: A descriptive study design was adopted. Snowball sampling technique was used to gather data from 108 adolescents in between the age group of 11 years to 19 years. A semi-structured questionnaire was used for the collection of data from the participants through an online survey. Results: Finding reveals that 26.85% of adolescents had good impact (Healthy dietary pattern), 51.85% had average impact (Moderate changes) and 21.29% had poor impact (Drastic changes) on dietary pattern. Related to lifestyle pattern results also revealed that 39.81% of adolescents had good impact (Healthy lifestyle), 51.85% had average impact ((Moderate changes)) and none of them had poor impact (Drastic changes) on lifestyle pattern. Conclusion: The ongoing COVID-19 pandemic has become a major public health concern and has changed the daily lives of citizens across the globe. Healthy eating and good life style pattern are key for health and well-being, especially when the immune system is challenged. The present study revealed a substantial increase in unhealthy dietary and lifestyle pattern among adolescents during COVID-19 lockdown.