The number of adolescent pregnancies in Indonesia is still very high. Sewon Subdistrict had the highest number of adolescent deliveries in Bantul District in 2015-2016. This study aimed to determine factors influencing exclusive breastfeeding among adolescent mothers in Sewon Subdistrict, Bantul District. This study used cross-sectional study design and a sample size of 45 that were adolescent mothers of 6-24-month-old infants. Data was collected using a structured questionnaire. Data analysis involved bivariate analysis using chi-square test and fisher’s exact test, while multivariate analysis used logistic regression. Results showed that 53.3% of adolescent mothers did not practice exclusive breastfeeding. Bivariate analysis showed that pregnancy status (p value = 0.029), perception of childbirth experience (p value = 0.045), perception of breastfeeding (p value = 0.005), husband support (p value = 0.009) and family support (p value = 0.000) were correlated to exclusive breasfeeding. Multivariate analysis showed that perception of breastfeeding (p value = 0.015; OR = 9.746) and family support (p value = 0.014; OR = 7.637) as the most influential factors to exclusive breastfeeding among adolescent mothers with a probability of 72.7%. There is low practice of exclusive breastfeeding among adolescent mothers in Bantul, Yogyakarta and family support is the most dominant factors influencing exclusive breastfeeding.