IntroductionDepressive emotions can lead to subsequent unhealthy behaviors such as Internet addiction, especially in female adolescents; therefore, studies that examine the relationships among depression, health‑related behaviors, and Internet addiction in female adolescents are warranted.PurposeTo examine (1) the relationship between depression and health-related behaviors and (2) the relationship between depression and Internet addiction.MethodA cross-sectional study design was adopted using a structured questionnaire to measure depression, health-related behaviors, and Internet addiction in female adolescents. The data were collected from students of a junior college in southern Taiwan using convenience sampling to select the participants. The questionnaire was divided into four sections: demographics, the Center for Epidemiologic Studies Depression Scale (CES-D), the Health Promoting Lifestyle Profile (HPLP), and the Internet Addiction Test (IAT).ResultsThe final sample comprised 503 female junior college students, with the participants mainly aged between 15 to 22 years (mean age = 17.30 years, SD = 1.34). Regarding the HPLP scores, the overall score, nutrition subscale score, and self-actualization subscale score were significantly and negatively associated with the CES-D depression score (p < 0.05–0.01). In other words, depression level was lower in students who exhibited more healthy behaviors, put more emphasis on dietary health, and had higher levels of self-admiration and confidence toward life. Regarding the IAT scores, the overall score and six domain scores were all positively associated (p < 0.01) to the CES-D depression score. In other words, the higher an individual’s Internet addiction score was, the higher her depression level was.ConclusionsThe results confirmed the relationship between depression, health-related behaviors, and Internet addiction. The cultivation of health-related behaviors may help in lowering depressive symptoms. Teenagers with depression have higher risks of developing Internet addiction, and such addiction is likely to affect their daily functioning.