Dry powder inhalers (DPIs) are commonly used for the delivery of inhaled medications, and should provide consistent, efficient dosing, be easy to use correctly, and be liked by patients; these attributes can all affect patient compliance and therefore treatment efficacy. The ELLIPTA(®) DPI was developed for the delivery of once-daily therapies for the treatment of asthma and chronic obstructive pulmonary disease. It has moderate resistance to airflow and can hold one or two blister strips, with each blister containing a sealed single dose of medication. Monotherapies can be delivered by the single-strip configuration and, in the two-strip configuration, one dose from each strip can be aerosolized simultaneously to allow combination therapies to be delivered, which enables the formulations for each product to be developed individually, since they are stored separately until the point of administration. There are three principal operating steps to administer a dose: open, inhale, close. This article summarizes the design, functionality, and in vitro dose-delivery characteristics of the ELLIPTA inhaler, and describes the results of human factors validation tests, designed to assess the performance of critical tasks required to use the inhaler. Results from the in vitro studies indicate that the ELLIPTA inhaler performs consistently with respect to in vitro dose delivery characteristics at a range of flow rates that can be achieved by the target population (≥30 L/min) and over its 30-day in-use life. Data from the human factors validation tests demonstrated that almost all participants (≥97%) were able to complete each of the steps required to prepare a dose for inhalation without error. Overall, the ELLIPTA inhaler has a versatile single- or two-strip design that allows it to be used for the delivery of a range of treatment options. It also improves patient ease-of-use when compared with the DISKUS(®) DPI.