Unintended perioperative hypothermia is associated with surgical site infection (SSI) in adults, prompting exhaustive efforts to maintain perioperative normothermia. Although these efforts are also made for pediatric patients, the association between hypothermia and SSI has not been demonstrated in children. We sought to determine whether perioperative hypothermia and other risk factors and clinical outcomes are associated with SSI in the pediatric population. This case-control study took place from January 2014 through December 2016 and included patients at a National Surgical Quality Improvement Program–participant academic children's hospital. All surgical patients were included in this retrospective analysis. SSI rates were determined. A univariate analysis was performed to determine clinical factors associated with SSI. A multivariate regression analysis was then performed to determine the predictive effect of minimum perioperative temperature for SSI. This study included 3541 patients, of which 92 (2.6%) developed SSI. A univariate analysis showed associations among SSI and higher perioperative temperatures, surgical specialty of otolaryngology and general surgery, and wound classification (American Society of Anesthesiologists ASA classification III and IV). A multivariate analysis determined the odds of SSI increased by a factor of 1.6 for every 1°C increase in minimum perioperative temperature. Unintended perioperative hypothermia in our pediatric patients was inversely associated with SSI. This finding suggests that pediatric SSI prevention may not require the efforts made for adult patients to maintain normothermia. •The rate of SSI was 3% among pediatric patients with no perioperative hypothermia.•The rate of SSI was 2% among pediatric patients with any perioperative hypothermia.•Minimum perioperative temperatures were higher among patients with SSIs.•Odds of SSI increase 60% for each 1°C increase in minimum perioperative temperature.