BACKGROUND: In this age of antimicrobial resistance, unnecessary use of antibiotics to treat non-bacterial acute respiratory tract infections (ARTIs) and inappropriate use of antibiotics in treating bacterial ARTIs are public health concerns. PURPOSE: Our aim is to identify the pattern of oral antibiotic prescriptions for outpatients with ARTIs in Japan. METHODS: We analysed health insurance claims data of patients (aged ≤74 years) from 2013 to 2015, to determine the pattern of antibiotic prescriptions for outpatient ARTIs and calculated the proportion of each antibiotic. RESULTS: Data on 4.6 million antibiotic prescriptions among 1559394 outpatients with ARTIs were analysed. The most commonly prescribed classes of antibiotics included cephalosporins (41.9%), macrolides (32.8%) and fluoroquinolones (14.7%). The proportion of first-, second- and third-generation cephalosporins was 1.0%, 1.7% and 97.3%, respectively. Fluoroquinolones accounted for a quarter of the prescriptions for ARTIs in patients aged >20 years. In contrast, penicillins accounted for just 8.0% of the total number of antibiotic prescriptions for ARTIs. CONCLUSIONS: According to clinical guidelines, penicillins are first-line antibiotics against ARTIs. However, third-generation cephalosporins, macrolides and fluoroquinolones are more frequently prescribed in Japan. Although we could not assess the extent to which appropriate antibiotics are selected, our results support the necessity of improving antibiotic choices in the treatment of ARTIs.