It is important for surgeons to understand patients' expectations for surgery. We asked whether patient factors and preoperative functional outcome scores reflect the degree of expectations patients have for posterior spinal surgery. Second, we asked whether patients' expectations for surgery predict improvements in functional outcome scores after surgery. We prospectively enrolled 155 consecutive surgical patients with greater than 90% followup. Patients' expectations were evaluated preoperatively along with SF-36 and Oswestry disability questionnaires. Postoperatively (6 months for decompression; 1 year for fusions), we quantified patient-derived satisfaction regarding whether expectations were met and by patient-derived functional outcome scores. In patients undergoing decompression, gender, SF-36 general health domain, and SF-36 physical component score predicted patients with high expectations for surgery. Patients with high expectations also reported greater postoperative improvements in SF-36 role physical domain scores after surgery. Expectations for surgery were met in 81% of patients. In a subset of patients (21 of 143), expectations were not met. These patients reported lower mean preoperative SF-36 general health, vitality, and mean mental component scores.