Internet addiction (IA) is a relatively new subject of study in academia, and it has several effects on a person's life in a variety of ways, including academic achievement, relationships, physical and mental health. Aim: To describe the effect of internet addiction on academic achievement among primary school children. Research Design: A descriptive research design was used in the current study. Settings: The study was applied in two primary schools in Sohag City. The Study Sample: A multi-stage random sample of 720 primary school children was recruited using a multi-stage random sample technique. Tools: There were three tools used in the current study, (I) demographic assessment tool, (II) Young's Internet addiction scale, and (III) academic achievement assessment tool. Results: more than half of the primary school children were female; the mean age them was 9.34 ± 1.64 years. Half of them spent 3-5 daily times on the internet. There was an association between internet addiction and academic achievement. The majority of primary school children agree to improve awareness about internet addiction and its effects through holding classes as proposed preventive interventions to reduce harm from IA. Conclusion: Excessive internet usage was shown to be one of the most common behaviors among primary school children, which can lead to addiction and harm their personal, social, and academic achievement. Recommendation: Children should be aware of the potentially detrimental effects of internet addiction, as well as the necessity to restrict internet usage, which can have a severe impact on kids' academic progress.