Introduction: The purpose of this study is to explore the effects of adventure education program for adolescents with internet addiction behavior. Methods: The adventure education courses were designed aiming at behavior improvement for internet-addicted adolescents. Quasi-experimental as well as the pretest-posttest nonequivalent groups design were used. Participants were 51 adolescents selected via "Diagnostic criteria for internet addiction" from one junior high school in Kaohsiung city and divided into two groups: an experimental group with participating in adventure education courses (n = 25) and a control group without participating in adventure education courses (n = 26). The intervention program consists of a series of designed adventure education courses (portable adventure activities, group orienteering, high and low ropes courses, hiking and biking challenge) within 44 hours in 6 weeks. To examine the effects of the adventure education program for the intervention, we applied the scale of "internet addiction" for measurement. Data analysis was then conducted by the SPSS 18.0 statistics software package with method of One-way ANCOVA. Results: Based on the research results, it was revealed that the experimental group with participating in adventure education courses decreased on internet-addiction and its five subscales (compulsive use, withdrawal symptoms, tolerance symptoms, interpersonal problems, health-related problems) than the control group (F value between 11.41 to 55.73, p < .05). Regarding the effect size (between .19 to .54), the low to medium levels of positive change were found for the experimental group. Conclusion: The adventure education courses designed as the intervention program in the current study could decrease the scores for internet addiction for adolescents after the courses. Finally, directions and implications for future researches (research participants, research design and multiple program design) and in program implementation (safety consideration emphasis, norm contact and connection, deepening reflection and debriefing) were suggested based on the results for the potential practical and theoretical contributions. [ABSTRACT FROM AUTHOR]