The Pain Self-Efficacy Questionnaire (PSEQ) is a valid and reliable patient-reported instrument used to assess pain self-efficacy in patients with chronic low back pain (CLBP). Recently, the 2-item (PSEQ-2) and the 4-item (PSEQ-4) short versions were developed showing satisfactory measurement properties in mixed chronic pain populations. The aim of this study was to examine responsiveness and minimal important change (MIC) of PSEQ, PSEQ-2 and PSEQ-4 in patients with CLBP. We used a sample of 104 patients undergoing multimodal physical therapy designed to partly change pain self-efficacy beliefs. Responsiveness was assessed by testing 16 a-priori formulated hypotheses regarding effect sizes, areas under the curve, and correlations with changes in other instruments measuring other constructs. The MIC was calculated using an external anchor specific for pain self-efficacy and the receiver operator characteristic method. The PSEQ and the PSEQ-4 met all hypotheses, while the PSEQ-2 met all but one. The MICs were: 5.5 for the PSEQ (9% of the scale range), 1.5 for PSEQ-2 (13% scale range) and PSEQ-4 (6% scale range). MIC values were different for patients with low or high baseline values for all three instruments. The PSEQ and its short versions are adequately responsive instruments in patients with CLBP.