Appropriate antibiotic prescribing is a core component of antibiotic stewardship programs to reduce the risk of antibiotic-resistant microbes. This study assessed the rate of misdiagnosed pediatric urinary tract infections (UTI) and associated antibiotic use following implementation of a quality improvement intervention. Using three interventions (diagnostic algorithm, callback system, standardized discharge antibiotic prescription), misdiagnosis of UTI decreased by half, and 2,128 antibiotic days were saved.