Objectives: This study was conducted to determine the relationship between Internet addiction and social adjustment, and test anxiety among the female students of Ardabil University of Medical Sciences. Methods: This descriptive correlational research was conducted on all female students of Ardabil University of Medical Sciences studying in the second semester of the academic year 2019. The sample consisted of 346 students who were selected by simple random sampling. Data were collected using three questionnaires assessing Internet addiction, social adjustment, and test anxiety. The obtained data were analyzed using Pearson correlation and regression analysis. Results: The results showed that there was a significant positive correlation between Internet addiction and test anxiety. There is also an inverse correlation between social adjustment and test anxiety. The results of step-by-step regression analysis showed that among the variables under study, the Internet addiction variable predicts 0.32 and along with the social adjustment variable 0.37 variance of test anxiety. Conclusions: It can be concluded that the level of test anxiety in students can be controlled through the necessary training to make better use of the Internet and prevent its addiction.