The purpose of the study was to examine the psychometric properties of the Coach-Athlete Relationship Questionnaire (CART-Q), an instrument that was originally developed and validated for British athletes (Jowett & Ntoumanis, 2004), with a sample of Belgian, Dutch speaking athletes. The CART-Q was designed to measure Closeness, Commitment, and Complementarity (3Cs). Study 1 focused on assessing the factorial validity of the 11-item CART-Q with a sample of 401 Belgian, Dutch speaking athletes employing Confirmatory Factory Analysis (CFA). Analysis pointed to a three-dimensional factor structure with satisfactory internal consistency scores. Study 2 cross-validated the factorial structure of the 11- item CART-Q with an independent sample of 400 Belgian, Dutch speaking athletes and examined its predictive validity. The three-dimensional factor structure was upheld with satisfactory internal consistency scores. The predictive validity of the Belgian CART-Q was demonstrated when the 3Cs of the CART-Q were associated with satisfaction variables in a conceptually coherent manner. Overall, results supported the multidimensional nature of the coach-athlete relationship with Belgian athletes, as reflected in the 3Cs.