Introduction: Despite advances in evidence-based smoking cessation approaches, quit rates in people with mental health conditions who smoke have not increased over the past decade. This research explored the role of family or peers in promoting smoking cessation in this population, using three specific aims; 1) examine the association between family or peer views on tobacco use and smoking cessation, 2) identify pathways through which family or peer factors influence smoking cessation, and 3) identify social barriers and facilitators to seeking cessation support when quitting. Methods: We used data from the Population Assessment of Tobacco and Health Study and collected qualitative data from people with mental health conditions who currently smoke or quit within the last five years. Data were analyzed using logistic regression modeling, structural equation modeling, and rapid qualitative analysis. Results: Having family or peers with positive or neutral views on tobacco use significantly reduced the odds of quitting smoking. Higher intentions to quit and changes in smoking behavior mediated the relationship between supportive family or peer behaviors and quitting smoking. Quitting together and encouragement from family or peers were perceived as supportive, while nagging the individual undermined quitting success. Except for individuals who regarded autonomy highly or were not ready to stop smoking, stronger social relationships and tailored support increased willingness to involve family members in cessation interventions. Conclusions: Supportive family or peer attitudes and behaviors can positively influence smoking cessation in people with mental health conditions who smoke. Ways to identify ideal family or peer support partners to involve in cessation interventions are proposed.