Background: Internet use is associated with social and psychological variables, especially in the adolescent’s population. The present study aimed to investigate the extent of internet addiction among higher secondary school going students and to examine the relationships between internet addiction, depression, anxiety, and stress. Method: The present study was a cross-sectional survey design conducted among higher secondary school students, purposive sampling technique was used to select the Higher Secondary School from Tezpur, Assam. Three hundred higher secondary school going students were randomly selected from Tezpur, Assam, using simple random sampling technique as per inclusion and exclusion criteria. Socio-demographic details were filled and subsequently, The Internet Addiction Test, Online Cognition Scales [OCS] and Depression Anxiety Stress Scale [DASS] were administered. Results: The prevalence of internet addiction was found to be 34% (severe internet addiction) among higher secondary school students. The study reported the presence of depression (11.3% mild level and 4.6 % moderate level), anxiety (6.5 % mild level and 4.6 % moderate level) and stress (20% mild level and 6.6% moderate level) among higher secondary school students. Online cognition score had significant positive correlation with depression, anxiety and stress. Conclusion: This research shows that internet addiction is present in the higher secondary school students and it has significant relationship with depression, anxiety, and stress. There is a need to explore interventions to deal with internet addiction in the school population.