Asthma and chronic obstructive pulmonary disease (COPD) have been viewed as distinct clinical entities. However, the distinction between the two is not always clear. Recently, much attention has been focused on patients with overlapping features of both asthma and COPD. The asthma–COPD overlap syndrome (ACOS) has been defined as symptoms of increased variability of airflow in association with an incompletely reversible airflow obstruction. Patients with ACOS have more dyspnea and wheezing, and experience more frequent exacerbations and worse outcomes compared with asthma or COPD alone. Inhaled corticosteroids (ICS) should likely be considered as part of the first line of therapeutics for individuals with ACOS. Ultimately, future research is needed to better delineate this group and further establish best appropriate therapeutic interventions.