BACKGROUND: According to the fear avoidance model, beliefs and thoughts can modify the outcome of patient with low back pain. The Back Belief Questionnaire (BBQ)-a 14 items scale-assesses these consequences of low back pain. OBJECTIVE: To test the psychometric properties of the French version of the BBQ. METHODS: The BBQ was translated using the forward-backward translation process. Throughout three repeated evaluation time points (D1, D7 and D30), various aspects of validity were analysed: acceptability, quality of items, unidimentionality, internal consistency, temporal stability (between D1 and D7), responsiveness (between D7 and D30), and construct validity comparing it to other validated scales. RESULTS: One hundred and thirty-one patients were enrolled and 128 were analyzed. The acceptability and the quality of the items were excellent. The scale was unidimensional and reliable (internal consistency: Cronbach's alpha = 0.8). The responsiveness was moderate but in line with other scores. The BBQ was, as expected, convergent with day-to-day activities and fear avoidance (FABQ and Tampa), disability (Quebec and Dallas scores), or anxiety and depression (HAD); and not correlated with pain. Best correlations were found with Tampa and FABQ. The temporal stability (test-retest reliability) was poor. However, similar changes were observed in near conceptual score (FABQ), which confirmed that clinical status may have not been stable and suggesting sensitivity to early changes for BBQ. CONCLUSIONS: The BBQ showed good psychometric properties to assess false beliefs and related fear in French or English LBP populations and can be used either for evaluation in international trials or as a part of self-care training.