This cross-sectional quantitative study was conducted to assess the presence of muscle dysmorphia (MD) and a drive for muscularity (DFM) in 1,039 personal trainers using the Muscle Dysmorphia Inventory (MDI) and the Drive for Muscularity Scale (DMS). Muscle dysmorphia is considered a subtype of body dysmorphic disorder that can be exacerbated by an intense DFM, which may in turn lead to negative psychobehavioral outcomes. Because personal trainers are an unresearched population with regard to these 2 constructs, a multidisciplinary framework was used to ground the present research study. Independent variables were structured using a biopsychosocial foundation where the biological dimension was operationalized through the Body Comparison Scale, the psychological dimension through the Symptom Checklist-90-Revised, and the social dimension through the Sociocultural Attitudes Towards Appearance Questionnaire-4. Kendall's tau-b revealed that general appearance concerns, muscle concerns, and somatic features were positively related to both MD and a DFM. A DFM and MD were significantly, positively correlated with internalization of thin ideals, muscular/athletic ideals, family and peer pressures, but not media pressures. All psychological variables were significantly, positively related to MD and a DFM. The DMS was able to significantly predict scores on the MDI using hierarchal multiple regression. Trainers who displayed MD and DFM symptoms did so with little disparity between the sexes. Trainers are in a unique position of instruction as well as guidance, and therefore a better understanding of how MD presents in this specific fitness arena may impact not only personal trainers, but also their clients through increased body image disturbance awareness as well as provide a new population of interest for future MD research.