OBJECTIVE:Smokers with bipolar disorder (BD) have low rates of successful quitting, yet no prior studies have evaluated the process of quitting among these smokers in the context of a current quit attempt. To facilitate development of more effective interventions, we conducted a qualitative exploration of challenges and facilitators of quitting in an intervention study for smokers with BD. METHODS:Participants were adult daily smokers with BD (n = 10) who completed a 10-week smoking cessation intervention consisting of Acceptance and Commitment Therapy (ACT) and nicotine patch. We administered semistructured interviews focused on the quitting process at the end of treatment and used inductive content analysis to extract themes. RESULTS:Emergent themes representing challenges of quitting included social impediments, lack of awareness, avoidance, maladaptive beliefs, ambivalence, benefits of smoking, and difficulties with nicotine replacement. Themes representing change facilitators included positive treatment effects (ACT-specific, nonspecific, and nicotine patch-related), coping behaviors, reasons to quit, changes in self-perception, and social benefits. CONCLUSIONS:Results suggest a need for assistance with obtaining social support and handling social impediments, interrupting the automaticity of smoking, expanding the behavioral repertoire to handle aversive internal states that tend to be avoided by smoking, preventing maladaptive beliefs from interfering with quitting, taking meaningful action toward change while experiencing ambivalence, either replacing the benefits of smoking or accepting their loss, and troubleshooting difficulties with nicotine replacement. Findings regarding facilitators of quitting supported previous quantitative findings that the ACT intervention impacted theory-based targets and highlighted the importance of the counseling relationship.