Though media attention increasingly highlights the difficult experiences mothers face when breastfeeding, only recently have researchers focused on breastfeeding conditions in work environments. Much of this newfound attention has focused on the physical structure of work (e.g., creating break rooms that can be reserved to pump while at work) or the presence of policies (e.g., allowing women to take company time to pump). However, the extant literature has not investigated the experiences of breastfeeding mothers who are balancing work and family demands simultaneously. Across two studies, we examine the daily experiences of women who are breastfeeding and/or pumping at work. In Study 1, we interviewed 38 women who provided insights surrounding daily episodes of breastfeeding and/or pumping at work and related affective, work, and family challenges. In Study 2, we developed and empirically tested a theoretical model based on Study 1 themes using an experience sampling method with 118 women surveyed three times a day for ten workdays. Results suggest that daily pressure surrounding breastfeeding/pumping at work increases affective strain, which lowers the amount of breastmilk produced, decreases work goal progress, and increases work-to-family interference. Additionally, the aforementioned effects are amplified for women who feel stigmatized for breastfeeding by colleagues.