Introduction: In the context of the lockdown due to Covid-19, usage of mobile phones has increased among adolescents. Usage of mobile phones for educational purposes as well as for entertainment makes them more addicted to mobile phones and electronic gadgets. In this scenario, Nomophobia, which is fear towards the situation when there is no phone, has increased among the adolescent. Aim: This research study aimed to prepare a nomophobic rating scale (NPRS) for adolescents and to implement it for students at the Higher secondary levels to check their nomophobic rate. Methods: In this study, investigators developed and standardized a Nomophobic rating scale to identify the addiction rate of Higher Secondary school students to mobile phones. Nomophobic Rating Scale was applied to 92 Higher Secondary Level students in Kerala and the collected data analyzed for evaluation. Results: The study shows that most of the students are prevalent to nomophobia. But the nomophobic rate does not depend on their locality, gender, course stream, but depend on the management of the school. Conclusion: This study points out certain serious concerns regarding the necessity of proper monitoring among adolescents about their usage of mobile phones. It also highlights the necessity of timely interventions on the part of teachers, parents and professionals which will invariably enhance the physical, social and emotional development of the students at the higher secondary level.