: Prevention of mother-to-child transmission (PMTCT) can virtually eliminate HIV infection among infants, yet up to one-third of women miss PMTCT steps. Little is known about how partner dynamics such as intimate partner violence (IPV) influence pregnant and postpartum women's adherence to PMTCT. We conducted 32 qualitative interviews with HIV-positive pregnant and postpartum women in Johannesburg who experienced IPV. Trained researchers conducted in-depth interviews over the period of May 2014-Nov 2015 using narrative and social constructionist approaches. Interviews were transcribed verbatim and analyzed thematically and inductively using Dedoose qualitative software. Twenty-six women experienced recent IPV and one-third had poor adherence to PMTCT. Women's experience of partner violence influenced PMTCT behaviors through four pathways. First, fear of partner disclosure led some women to hide their HIV status to avoid a violent reaction. Despite strategic non-disclosure, several maintained good adherence by hiding medication or moving out from their partner's home. Second, IPV caused feelings of depression and anxiety that led to intentionally or accidentally missing medication. Five women stopped treatment altogether, in a type of passive suicidality, hoping to end the distress of IPV. Third, men's controlling behaviors reduced access to friends and family, limiting social support needed for good adherence. Fourth, in a protective pathway, women reported good adherence partly due to their mothering role. The identity around motherhood was used as a coping technique, reminding women that their infant's wellbeing depended on their own health. PMTCT is essential to prevent vertical HIV transmission, but women living with IPV face multiple pathways to non-adherence. Addressing IPV in antenatal care can support the health of women and infants and may enhance PMTCT coverage.<br/>