: Despite the numerous health benefits of exclusive breastfeeding (EBF) for the infant and the mother, EBF rates in Lao People's Democratic Republic, Lao PDR, remain at 40%. We investigate how barriers to EBF were overcome by a social transfer intervention. : Data from the Social Transfers for Exclusive Breastfeeding ongoing randomised controlled trial (RCT) ( = 298) in Vientiane, Lao PDR, was used. Mothers in the RCT were randomised equally into a control group, an unconditional transfer group and a conditional transfer group and followed up to six months ( = 280). We used logistic and Cox proportional hazards regression models to investigate the association of predictor variables with EBF at six months and the risk of EBF cessation in each of the three groups. : Greater breastfeeding self-efficacy increased the odds of EBF at six months in both intervention groups (unconditional transfer OR 1.39 [95% CI 1.09, 1.87, = 0.02] and conditional transfer OR 1.26 [1.01, 1.61, = 0.05]) and reduced the risk of EBF cessation (unconditional transfer HR 0.87 [0.77, 0.98, = 0.02]). Maternal secondary and tertiary education in the intervention groups showed higher odds of EBF at six months and lower EBF cessation risk. Participants in the intervention group that intended to exclusively breastfeed in pregnancy showed a reduced EBF cessation risk in both intervention groups. : Social transfers helped overcome the exclusive breastfeeding barrier of a higher education level and working status and improved EBF outcomes for mothers who intended to exclusively breastfeed and wanted the pregnancy. Breastfeeding self-efficacy positively influences EBF outcome, regardless of whether the mother received a social transfer or not.