Background and aim: Attention-Deficit/Hyperactivity Disorder (ADHD) is one of the most prevalent psychiatric disorders that begins in childhood. Research has shown that individuals with ADHD have a different perception of time compared to others. One of the most common comorbidities linked to ADHD and addictive behaviors in the current generation is internet addiction, which is also affected by an individual's perception of time. Therefore, this study aims to explore the relationship between elements of time perception and internet addiction in adolescents with ADHD. Material and Methods: In this descriptive-correlational study, 136 adolescents diagnosed with ADHD by a psychiatrist were selected using purposive sampling and completed the Young Internet Addiction Test and the Zimbardo Time Perspective Inventory (ZTPI). Data analysis was performed using SPSS software. Results:The present study showed that 1.47% of the participants had Internet addiction, and 33.82% of the participants were at risk of Internet addiction. Also, different components of time perspective are related to Internet addiction in adolescents with ADHD. Negative past time perspective and hedonic present time perspective were positively correlated with Internet addiction, with p = 0.37 and p = 0.242, respectively, and future time perspective was negatively correlated with Internet addiction in adolescents with p = -0.246. Conclusion: The time perspective of adolescents with ADHD can predict their internet addiction. From a practical standpoint, it appears that therapeutic interventions based on reconstructing attitudes toward time in adolescents with ADHD may lead to a reduction in their internet addiction and an improvement in symptoms.