BACKGROUND Screen use time has increased in the past decade owing to the increased availability and accessibility of electronic devices and the internet. Several studies have shown an association between increased screen use time and mental health issues like anxiety and depression. However, screen use is vital to modern life. It thus becomes pertinent to establish thresholds for screen use time to protect one’s mental well-being. OBJECTIVE We aim to measure the self-reported screen use times and patterns in young adults (18-24 years) in India, study the hypothesis that increased screen use time is associated with poorer mental well-being, and establish thresholds for ‘safe’ screen exposure time. METHODS This protocol describes a cross-sectional study of a pan-India online convenience sample of young adults that have access to digital devices with a screen and a minimum of secondary school education. Participants will be recruited through a network of collaborators via social media while data will be collected through Google forms. Socio-demographic details will be collected through a questionnaire designed by the authors; screen use time and patterns will be assessed using an adaptation of the screen time questionnaire to include data on different applications and websites used on electronic devices; while mental health parameters will be gauged using the Warwick-Edinburgh mental well-being scale, Generalized Anxiety Disorder (GAD)-7, Perceived Stress Scale (PSS)-10, and Patient Health Questionnaire (PHQ)-9. To quantify the association between the screen use time with mental health, a Bayesian multivariate multiple regression analysis will be performed which models the possibility of multiple alternative hypotheses while accounting for relevant socio-demographic covariables. RESULTS We have designed the questionnaire (survey instrument) and have received feedback from domain experts. We have not yet initiated the data collection and the results obtained will be updated accordingly. CONCLUSIONS This study could help better understand the role of screen time use on mental health, and determine the healthy levels of use in India, where the largest young adult population resides.