Exercise addiction is a morbid-compulsive behavioral pattern characterized by a loss of control over exercise and which results in major detrimental consequences in the affected individual’s life. Although the condition is not formally recognized in official psychiatric texts, exercise addiction can lead to clinical impairment of everyday activities just like other more traditional addictions. This has led to the development of many instruments to assess exercise addiction. One of the most widely used instruments is the Exercise Addiction Inventory (EAI) which has been translated into a number of languages and has separate versions of the scale for adults and adolescents (i.e., the EAI-Y for youth). However, there are currently no Persian versions. Therefore, the present study translated the EAI into Persian and assessed its psychometric properties using Rasch analysis among both Iranian adults (n = 745, age range = 19–30 years, 60.53% female) and Iranian adolescents (n = 562, age range = 13–18 years, 62.45% female). An online survey was used to collect data from September to November 2021. Confirmatory factor analyses and the Rasch analyses confirmed the unidimensional structure of the EAIs and good reliability using the Omega coefficient (.71 to.72). Also, separation reliability on item, scale, and person-level was established, along with supported measurement invariance, demonstrating that EAI can discriminate individuals on a high or low level of exercise addiction independent of their age and gender. Overall, the Persian EAI demonstrated sound psychometrics in screening for exercise addiction among Iranian adults and adolescents.