Asthma is a chronic inflammatory airway disease, for which the cornerstone of asthma therapy is inhaled corticosteroids. However, long term clinical outcomes are variable, and not all patients respond optimally to corticosteroids. Underpinning this observation is that asthma is a heterogeneous disease consisting of phenotypes that are driven by different inflammatory pathways. In this article, we will discuss the different inflammatory mechanisms of asthma to better define patient characteristics and help improve patient outcomes with newer specific-targeted asthma therapies.