Factors which are barriers to preschool teachers' use of English as the medium of instruction and facilitating strategies used to overcome those barriers can be complex. This study investigated those barriers and facilitating strategies through a systematic review using various databases, which resulted in 20 studies being identified. From these studies, barriers and facilitating strategies were found and arranged in two main categories: (1) barriers to, and facilitating strategies of, preschool teachers' use of English during instruction as it relates to the teachers themselves, and (2) barriers to, and facilitating strategies of, preschool teachers' use of English during instruction as it relates to the learning environment. The results provided an overview and a lead into a better understanding of issues faced by preschool teachers in their use of English to teach, whilst also identifying positive strategies to assist them during their instructional tasks. The factors and strategies identified are important as a guide for preschool policy makers towards future planning of practices and further research.