Breastfeeding is the most advantageous feeding option for infants, and epidemiological studies provide evidence for its promotion. The objective of this review was to comprehensively delineate the barriers and facilitators of exclusive breastfeeding of infants aged 0-6 months old by mothers in developing countries. A search of CINAHL, MEDLINE and PsycINFO was carried out to retrieve studies from January 2001 to January 2014. Using our inclusion criteria, we selected studies that described barriers and facilitators of exclusive breastfeeding. Qualitative and quantitative studies were considered. Twenty-five studies involving 11 025 participants from 19 countries were included. Barriers and facilitators of exclusive/full breastfeeding were identified, analysed tabulated and summarised in this review. Maternal employment was the most frequently cited barrier to exclusive breastfeeding. Maternal perceptions of insufficient breast milk supply was pervasive among studies while medical barriers related to illness of mothers and/or infants as well as breast problems, rather than health care providers. Socio-cultural factors such as maternal and significant other's beliefs about infant nutrition also often constitute strong barriers to exclusive breastfeeding. Despite these barriers, mothers in developing countries often possess certain personal characteristics and develop strategic plans to enhance their success at breastfeeding. Health care providers should be informed about the determinants of exclusive breastfeeding and provide practical anticipatory guidance targeted at overcoming these barriers. In so doing, health care providers in developing countries can contribute to improving maternal and child health outcomes.