Although less frequent than the primary spontaneous pneumothorax (PSP), secondary pneumothoraces (SP) are a common clinical problem with a wide range of severity, depending on the triggering cause(s) and patient clinical condition. By definition, an SP occurs in those patients with an underlying condition that alters the normal lung parenchyma and/or the visceral pleura and determines air entry in the pleural space (e.g., COPD) or, eventually, following trauma or invasive procedures (i.e., iatrogenic pneumothorax). Less frequent, yet described, is SP occurring in neoplastic patients or infectious ones. The gravity of an SP is directly correlated to the underlying cause and patients’ clinical conditions. For example, it may be a life-threatening condition in an end-stage COPD but less severe in a catamenial related syndrome. In this chapter, we are providing a surgical overview of the most relevant and updated information on etiology, incidence, pathophysiology, and management of secondary pneumothoraces.