Muscle dysmorphia (MDM), or bigorexia, is a subcategory of body dysmorphic disorder (BDD), also known as "Adonis Complex" in nonscientific contexts. One of the most used tools to investigate MDM is the Adonis Complex Questionnaire (ACQ). The ACQ is a 13-item US questionnaire, designed for male subjects only, related to the dissatisfaction and concerns about physical appearance. The aim of the current study was to evaluate the validity of the Italian version of the ACQ.