 Chronic obstructive pulmonary disease, COPD, is characterized by increased production of reactive oxygen species, ROS, which can lead to cellular damage and inflammation. While there is evidence suggesting that ROS play a role in the development and progression of COPD, the exact mechanisms remain unclear. This review examines the sources of ROS, the defenses that exist to protect against them, and the potential for targeted treatments to reduce the damage caused by ROS. It also highlights the need for further research into the role of ROS in COPD. This article was authored by Adam John Anthony McGinnis and Elizabeth Sapey.