This qualitative study examines women's experiences with antiretroviral therapy (ART) adherence and retention in Option B+ care among 39 pregnant and lactating women in Bwaila Hospital, Lilongwe, Malawi. Study participants included 14 in care and 25 out of care women, according to facility records. One of the most important factors influencing adherence and retention was the strength of women’s support systems. In contrast to women in-care, most out-of-care women lacked emotional and financial support from male partners, received minimal counseling from providers at initiation, lacked designated guardians to assist with medication refills or clinic appointments, and were highly mobile. Mobility led to difficulties in accessing treatment in new settings. The most common reasons women re-started treatment following interruptions were due to providers’ counseling and encouragement and the mother’s desire to be healthy. Improved counseling at initiation, active follow-up counseling, women’s economic empowerment interventions, promotion of peer counseling schemes and meaningful engagement of male partners can help in addressing the identified barriers and promoting sustained retention of Option B+ women.