Pediatric antibiotic prescriptions originate from an increasingly broad range of ambulatory settings. In this retrospective study, pharyngitis, otitis media, sinusitis, pneumonia, and upper respiratory infection cases, at 11 primary care offices, 2 independent urgent care centers (UCCs), and a pediatric emergency department in Western New York, were analyzed relative to medical society practice guidelines and antibiotic utilization. Of 2358 eligible visits across all sites, 25% were for study diagnoses, with 38% at UCC ( P < .01). Across all sites, 26% of pharyngitis cases given antibiotics did not have diagnostic evidence of bacterial infection. At primary care offices and UCCs, guideline recommended first-line agents for pharyngitis and otitis media were used in only 58% and 63% of treated cases, respectively. Overall, an estimated 9855 to 12 045 avoidable antibiotic and 8030 non-guideline antibiotic courses annually are represented by the 14 sites studied. These and other study findings highlight numerous opportunities for outpatient pediatric antibiotic stewardship.