The purpose was to determine whether psychosocial factors are associated with cessation among smokers interested in quitting. This cross-sectional study included 403 current and former smokers enrolled in a 'Quit and Win' contest. After the quit period, data were collected via a telephone interview at three months post-baseline. Controlling for demographics and secondhand smoke exposure, lower depressive symptoms and more positive partner or friend support to quit predicted a greater likelihood of quitting. Integrated interventions that combine tobacco treatment with mental health strategies to reduce depressive symptoms and improve partner or friend interactions may be most effective with smokers interested in quitting.