This study was designed to evaluate the influence of gender on the inhaler technique of subjects on inhaler therapy and to determine the factors predicting the correct inhaler technique and a change of inhaler device.A total of 568 adult subjects (276 male, 292 female) on inhaler therapy were included in this cross-sectional, observational study. Data on sociodemographic characteristics, inhaler therapy, subject-reported difficulties, and technician-reported errors in inhaler technique were recorded.A change of inhaler device was noted in 71.0% of male subjects and 77.4% of female subjects, and this was based on the physicians' decision in most cases (41.7% and 51.7%, respectively). A higher percentage of female subjects reported difficulties with using inhalers (63.7% vs 40.6%, < .001). Overall, having received training on the inhaler technique was associated with a higher likelihood of correct inhaler technique (odds ratio 12.56, 95% CI 4.44-35.50, < .001) and a lower risk of device change (odds ratio 0.46, 95% CI 0.27-0.77, = .004).Errors in the inhaler technique, including inhalation maneuvers and device handling, were common in subjects on inhaler therapy. Subject-reported difficulties with using inhalers were more prevalent among female subjects, whereas errors in the inhaler technique identified by direct observation were similarly high in both genders. Overall, a lack of training on the inhaler technique predicted a higher likelihood of errors in the inhaler technique and a change of inhaler device.