Objectives: People living with a psychotic illness have higher rates of cigarette smoking and face unique barriers to quitting compared to the general population. We examined whether self-reported reasons for smoking are useful predictors of successful quit attempts among people with psychosis. Methods: As part of a randomized controlled trial addressing smoking and cardiovascular disease risk behaviors among people with psychosis, self-reported reasons for smoking were assessed at baseline (n = 235), 15 weeks (n = 151), and 12 months (n = 139). Three factors from the Reasons for Smoking Questionnaire (Coping, Physiological, and Stimulation/Activation) were entered into a model to predict short-and long-term abstinence. The relationship between these factors and mental health symptoms were also assessed. Results: Participants scoring higher on the Stimulation/Activation factor (control of weight, enjoyment, concentration, and "peps me up") at baseline were just less than half as likely to be abstinent at 15 weeks. Female participants were five times more likely to abstinent at 15 weeks, and those with a higher global functioning at baseline were 5% more likely to be abstinent. There was a positive correlation between changes over time in the Stimulation/Activation factor from baseline to 12-month follow-up and the Brief Psychiatric Rating Scale total score at 12-month follow-up. This indicates that increasingly higher endorsement of the factor was associated with more psychological symptoms. There was also a negative correlation between the change over time in the Stimulation/Activation factor and global functioning at 12 months, indicating that increasingly higher endorsement of the factor led to lower global assessment of functioning. Conclusions: The Stimulation/Activation factor may be particularly important to assess and address among smokers with psychosis. It is recommended that further research use the Reasons for Smoking Questionnaire among smokers with psychosis as a clinical tool to identify specific quit barriers. Further research into why females have higher smoking cessation rates in the short term and relapse prevention interventions seem worthy of further investigation.