Asthma remains one of the most common diseases worldwide and results in significant societal health care costs and in morbidity and mortality to those afflicted. Despite currently available medications, 5-10% of patients with asthma have severe disease with debilitating symptoms and/or life-threatening exacerbations. Bronchial thermoplasty is a device-based therapy with proven efficacy in this subgroup of patients. Thus far, bronchial thermoplasty has been shown to reduce exacerbations and to improve important measures of asthma control. The purpose of this article is to review the pathophysiology of severe asthma, including the role of airway smooth muscle cells and the procedural aspects of bronchial thermoplasty, and to review the evidence behind this important therapy.