A significant proportion of women who self-quit smoking during pregnancy subsequently relapse to smoking post-partum. This study examined free-text responses describing attributions of smoking relapse or maintained abstinence at 1, 8, and 12 months post-partum. This study reports secondary analyses from a randomized clinical trial (N = 504) for preventing post-partum smoking relapse. At each follow-up, one survey item asked the participant to describe why she resumed smoking or what helped her maintain abstinence. A thematic content analysis was conducted on responses from the 472 participants (94.0 % of the original sample) who returned at least 1 survey. Content analyses revealed several themes for participants' reasons for relapse and abstinence. Stress was the most frequently cited reason for smoking relapse across all follow-ups. Health concerns for children and family was the most common reason provided for remaining abstinent. Chi square analyses revealed differences in written responses related to income, age, and depressive symptoms. Overall, these findings suggest that during the post-partum period, stress and familial health concerns are perceived contributors to smoking relapse and abstinence, respectively. These results confirmed key risk and protective factors that have been identified through other assessment modalities (e.g., quantitative surveys and focus groups). They also provide support for targeting these variables in the development, content, and delivery of future post-partum smoking relapse-prevention interventions. The high response rate to these open-ended attribution questions suggests that future studies would benefit from including these and similar items to allow for additional insight into participant perspectives.