Background <p>Studies shows that there is a relationship between internet addiction and ADHD symptoms, especially inattention. A study found that there is a unique relation between each core ADHD symptom and different types of internet activities. Another study found that deficits in inhibitory control moderate the relationship between internet addiction and inattention. Therefore, this study aimed to explore how specific online activities might modify the relationship between inattention, internet addiction and inhibitory control.</p> Methods <p>205 participants (79 females,126 males) between 18 and 49 years old took part in the study from a community sample. They completed the demographic information form, Adult ADHD Self-Report Scale Symptom (ASRS-v1.1) Checklist, and Young’s Internet Addiction Test (IAT) online. Then, they performed the Stroop Task.</p> Results <p>Consistent with previous research we show that inattention predicts internet addiction, and that this relationship is moderated by inhibitory control ability; the relationship between inattention and internet addiction strengthens as executive function impairment increases.</p> Conclusions <p>These results indicate that ADHD symptoms and executive function impairments interact in a way that leads to real-life consequences, even when there is no relationship between those symptoms and executive function performance. Furthermore, we show that no single online activity is responsible for the relationship between inattention and internet addiction, nor does inhibitory control ability determine which online activity participants engage in.</p>