The COVID-19 pandemic is a once-in-a-lifetime incident whose impact touched everyone from all walks of life. Such an unparalleled global event warranted unprecedented measures to mitigate the imminent public health catastrophe and protect risk groups. However, these actions have inevitably marginalized the physical and mental health of adolescents who were at a lower threat of adverse physical outcomes from COVID-19 infection. Restrictive public health measures resulted in disruption of routines from the closure of the school and public spaces, social isolation, loneliness, lack of engagement, and boredom. These impacts culminated in physical inactivity, sedentary lifestyle, eating disorders, and obesity and led to physical changes that have long-term implications. Equally, the substantial psychological stress of the pandemic resulted in an increased report of anxiety, depression, behavioral problems, and suicide attempts among adolescents in both previously healthy and those with pre-existing mental conditions. This narrative review provides a brief overview of the current evidence of the physical and mental impact of the pandemic lockdown on adolescent health and discussed interventional implications.