In the contemporary era characterized by technological advancements, teenagers are displaying a growing inclination towards acquiring access to health-related information, which is crucial for teenagers to make informed decisions on their overall health and well-being. The findings indicate that the Internet is the primary source of health information, followed by kin and acquaintances, mass media, and medical practitioners among teenagers in Sri Lanka. Gender is a significant factor, as males prefer utilizing mass media and the internet, whilst females tend to rely more on medical practitioners, kinship networks, and friends. Education has a significant impact on teenagers’ health information-seeking behaviour; low-education teenagers depend more on kin and acquaintances, while higher-education teenagers are more inclined to utilize the Internet. Moreover, highly physically active teenagers rely on kin and acquaintances, while less active tend to rely on the Internet. The findings of the multinomial regression analysis emphasize that teenagers mostly rely on the Internet and medical experts in Sri Lanka. Education, perceived severity of health conditions, and health efficacy have an impact on these behaviours. This study adds to the body of knowledge regarding the information-seeking behaviours of teenagers, offering significant insights that can inform the progress of customized health promotion strategies and culturally appropriate digital health communication.