Background: Problematic internet use negatively affects adolescents' health behaviors and school success. Purpose: This study evaluated the effects of a solution-focused approach (SFA) on adolescents' problematic internet use, health behaviors, and perceived academic success. Methods: A randomized controlled experimental design was used with pre-test–post-test. The sample comprised 128 middle school students, with 64 in the intervention group and 64 in the control group. Data were collected using an information form, Young's Internet Addiction Test, the Nutrition–Exercise Behavior Scale, and the Nutrition–Exercise Attitude Scale. The intervention group attended six SFA group meetings. Results: “The intervention group's, mean pre- and post-test internet addiction scores were 35.65 ± 4.43 and 17.07 ± 5.01, respectively. There were statistically significant differences between the post test groups (p < 0.05) for mean internet addiction, total nutrition–exercise attitude, and total nutrition–exercise behavior and subdimension (except regular meals) scores and perceived academic success. Implications for practice and research: SFA may prevent students' uncontrolled internet use, help them gain positive health behaviors, and increase perceived academic success. The school nurse, on the other hand, may support the adolescent and their families with solution-focused interview strategies.