This study examined the factor structure of the Pain Catastrophizing Scale in three different Dutch-speaking samples: 550 pain-free students, 162 chronic low back pain patients, and 100 fibromyalgia patients. Confirmatory factor analyses were used to compare three different models of pain catastrophizing (one factor, two oblique factors, three oblique factors), and to investigate the invariance of the factor structure across the three different samples. The results indicated that a three-factor oblique model with a four-item rumination factor, a three-item magnification factor, and a six-item helplessness factor provided the best fit to the data in the three samples. Furthermore, it was found that this model could be considered as invariant across three samples (pain-free students, chronic low back pain patients, and fibromyalgia patients) and across gender, indicating that the same processes are measured in different subgroups.