This study aims to investigate the prevalence of short-acting β2-agonist (SABA) overuse in asthma and the associated risk of acute exacerbation and mortality in Taiwan. We used the Taiwanese pay-for-performance asthma program database, which included patients aged between 12 and 100 years who were enrolled in the program between 2001 and 2015. Among a total of 218,039 patients, 34,641 (15.9%) patients are classified as SABA over-users. Compared with patients who did not receive inhaled corticosteroids (ICS) and collected ≤2 canisters, SABA over-users had a higher risk of severe exacerbations. SABA over-users had a higher risk of all-cause mortality compared with patients who did not receive ICS and collected ≤2 canisters. The overall prevalence of SABA overuse in Taiwan is 15.9%, and this is even higher in concomitant ICS users. In addition, the overuse of SABA is associated with an increased risk of severe exacerbation and death.