Patients undergoing thoracic surgery experience high complication rates. It is uncertain whether preoperative health-related quality of life (HRQOL) measurements can predict patients at higher risk for postoperative complications. The objective of this study was to determine the association between preoperative HRQOL and postoperative complications among patients undergoing thoracic surgery. This was a retrospective cohort study of prospectively collected data. Consecutive patients undergoing elective thoracic surgery at a Canadian tertiary care centre between January 2018 to January 2019 were included. Patient HRQOL was measured using the Euroqol-5 Dimension (EQ-5D) survey. Complications were recorded using the Ottawa Thoracic Morbidity and Mortality system. Uni- and multivariable analysis were performed. Of 515 surgeries performed, 133 (25.8%) patients experienced at least one postoperative complication. 345 (67.0%) patients underwent surgery for malignancy. A range of 271 (52.7%) to 310 (60.2%) patients experienced pain/discomfort at each timepoint. On multivariable analysis, lower preoperative EQ-5D visual analogue scale scores were significantly associated with postoperative complications [adjusted odds ratio 0.97, 95% confidence interval 0.95-0.99; p = 0.01]. Presence of malignancy was not independently associated with complications (p = 0.68). Self-reported preoperative HRQOL can predict incidence of postoperative complications among patients undergoing thoracic surgery. Assessments of preoperative HRQOL may help identify patients at higher risk for developing complications. These findings could be used to direct preoperative risk-mitigation strategies in areas of HRQOL where patients suffer most, such as pain. The full perioperative trajectory of patient HRQOL should be discerned to identify subsets of patients who share common risk factors.