Purpose: Fluoride toothpastes are effective in caries prevention. In legislation, regular fluoride toothpaste is a cosmetic product; adolescents use it for aesthetic purposes. In dentistry, fluoride toothpaste is considered a caries preventive drug recommended to patients for that reason. Knowledge is lacking concerning what motivates adolescents to use fluoride toothpaste. Dental professionals need to understand how to motivate a risk-group for caries development to use fluoride toothpaste frequently in order to effectively motivate patients to prevent tooth decay. The purpose of this study was to investigate what motivates adolescents to use fluoride toothpaste. Materials and Methods: The study was conducted at a high school in southern Sweden. The final sample consisted of 16 adolescents age 16 to 19. This study employed a qualitative design using semi-structured interviews. The data were analysed using manifest content analysis with an occasional inductive approach. Results: Reasons for why adolescents use fluoride toothpaste were found in four different categories: oral health, economy, upbringing and habit, social influences. Conclusion: There are reasons to believe that dental professionals might have missed important arguments for why adolescents use fluoride toothpaste. The participants mentioned oral health and aesthetics as important reasons for using fluoride toothpaste, as well as other more surprising factors such as financial reasons and social environment. There are thus more arguments for using fluoride toothpaste that adolescents value than the ones we believe dental professionals use. Keywords: adolescents, fluoride toothpaste, oral health behavior, motivation, qualitative research