Smoking cessation during pregnancy is often temporary; many women relapse postpartum. To develop strategies for supporting successful long-term smoking cessation, we conducted a qualitative study to explore the influence of couple interactions on women's tobacco reduction within the context of pregnancy and the postpartum period. A total of 28 women who quit or reduced smoking for pregnancy and their partners were interviewed following delivery and at 3-6 months postpartum. Open-ended, individual interviews elicited the challenges posed by the women's tobacco reduction and how their partners influenced their cessation efforts. The use of constant comparative analytic strategies focusing on women's processes, experiences, and responses revealed that unquestioned expectations for pregnant women's cessation created the social context of compelled tobacco reduction. Women's engagement in tobacco reduction in this context fundamentally altered couples' previously established tobacco-related routines. The intensity of these changes varied depending on the couples' established interaction patterns with respect to tobacco (i.e., disengaged, conflictual, or accommodating) and was a source of conflict for some couples. The findings offer novel ways to understand smoking cessation during pregnancy that provide new directions for research and for tailoring smoking cessation interventions.