Methods: LSS patients who underwent decompression surgery with or without fusion were included. Clinical outcomes were measured before surgery and 6 months postoperatively using the Zurich Claudication Questionnaire (ZCQ); Visual Analog Scale (VAS) of low back pain, leg pain, and leg numbness; Japanese Orthopaedic Association Back Pain Evaluation Questionnaire; and the Medical Outcomes Study 36-item Short-Form General Health Survey (SF-36). The Hospital Anxiety and Depression Scale (HADS), Pain Catastrophizing Scale, and Pain Anxiety Symptoms Scale were used to evaluate psychological status before surgery. Patients were classified as satisfied or dissatisfied with surgery based on a ZCQ satisfaction subscale cutoff score of 2.5. Results: The satisfied and dissatisfied groups contained 128 and 29 patients, respectively. Six months postoperatively, outcome scores for the dissatisfied group were unchanged or worse than preoperative scores (p>0.05). Multivariate logistic regression analysis showed significant associations between dissatisfaction and preoperative low back pain VAS score ≥ median (odds ratio [OR], 0.27; 95% confidence interval [CI], 0.10–0.74; p=0.01), preoperative mental health SF-36 score ≥ median (OR, 0.26; 95% CI, 0.08–0.89; p=0.03), and preoperative anxiety HADS score ≥ median (OR, 3.95; 95% CI, 1.16–13.46; p=0.03). Conclusions Preoperative less severe low back pain, lower mental health, and higher anxiety are associated with patient dissatisfaction with lumbar surgery, not depression, pain catastrophizing, or fear-avoidance beliefs. Pre- and postoperative psychological status should be assessed carefully and managed appropriately.