Abstract Background: Understanding how adolescents acquire health knowledge and where they currently seek answers to health-related questions may facilitate the development of interventions that will be both engaging and effective, and may help to improve health over the short- and long-term. Objective: The present study sought to investigate the perception and use of sources of health knowledge by young adolescents as stratified by gender. Methods: Thirty 50-min long focus groups were conducted with 143 participants. Focus group questions were built around the following three main categories: sources of knowledge, including preferred sources, sources accessed for general health, and sources accessed for personal/sensitive health; health information and behaviour change, including characteristics of health knowledge presentation that have influenced behaviour change; and learning preferences to promote behaviour change. Content analysis of focus group transcripts was performed. Results: The use of sources of health knowledge was similar between genders, with some differences noted between sources accessed for general as compared to personal health questions. As well, motivation appeared to be the primary influence of health behaviour change, with knowledge being reported as both as positive and neutral influence, most notably in the areas of diet and exercise. Lastly, adolescents reported several characteristics of health knowledge presentation that they felt would motivate positive behaviour change, including engaging and participatory activities. Conclusion: These results should be considered in the development of interventions to improve health-related behaviour in adolescents, although future research to quantify the use of sources of health knowledge by this population is recommended.