Objective: Adolescents’ leisure activities are increasingly focusing on Internet activities, and today, these coexist with traditional leisure activities such as sport and meeting friends. The purpose of the present study was to investigate leisure activities, particularly Internet activities, among boys and girls with ADHD, and compare these with boys and girls from the general population. The objective was also to explore how traditional leisure activities and Internet activities interrelate among adolescents with ADHD. Method: Adolescents with ADHD (n = 102) were compared with adolescents from the general population on leisure activities and Internet use. Results: Leisure activities among adolescents with ADHD tended to focus on Internet activities, particularly online games. Internet activities were broadening leisure activities among adolescents with ADHD, rather than being a substitute for traditional leisure activities. Conclusion: Internet activities may provide adolescents with ADHD accessible means of social interaction.