Aim Although the importance of biopsychosocial models for chronic diseases is emphasized nowadays, the lack of assessment tools to meet this need draws attention. This study was planned to assess the validity, reliability, and responsiveness of the Cognitive Exercise Therapy Approach-Biopsychosocial Questionnaire (BETY-BQ) in patients with fibromyalgia. Method Hospital Anxiety and Depression Scale (HADS), Mindful Attention Awareness Scale, Health Assessment Questionnaire, the Fibromyalgia Impact Questionnaire, and Short-Form 36 (SF-36) were used for the validity of BETY-BQ. For the reliability study, evaluations were repeated at 1-week intervals and for the responsiveness, the same scales were applied to patients under medical treatment at 3-month intervals. Results The correlations of BETY-BQ with the other scales were found to be moderate to high (respectively r = .591, P r = .441, P r = -.419, P r = .617, P r = .722, P r = -.580 and -.374, P = .001 and P < .001) and with SF-36 sub-parameters were found to be weak-moderate. The test-retest method was used for reliability, and the correlation between the responses was very high (r = .901, P < .001). The intraclass correlation coefficient (ICC) was found to be high (ICC = 0.899, P < .001). Cronbach's alpha (alpha) value was found to be .947. In the correlation analysis of time-dependent changes, BETY-BQ correlated weakly with other scales and moderately correlated with HADS (HADS-anxiety r = .489, P = .006, HADS-depression r = .500, P = .005). Conclusions BETY-BQ was presented in the literature as a valid, reliable, and sensitive scale that can be used both in the biopsychosocial evaluation and as an easily understood, practical scale that can be answered in a short time in the practices of healthcare professionals.