Posttraumatic stress disorder (PTSD) is associated with a high prevalence of cigarette smoking, heavy cigarette consumption, and low cessation rates. To date, little is known about mechanisms impeding smoking cessation among this recalcitrant group of smokers. An important first step in improving smoking cessation treatment efficacy is the assessment of knowledge about mechanisms pertinent to relapse. This theoretical study addresses the gap in the literature regarding factors potentially influencing smoking relapse among individuals with PTSD. Mechanisms reviewed that may be particularly relevant to smoking relapse among PTSD smokers include negative affect, positive affect, attention, anxiety sensitivity, distress tolerance, and self-efficacy. Treatment implications as well as methodological advances that may be relevant to examining the proposed relapse model are discussed.