Our understanding of the composition of the microbial communities that inhabit the human body, known as the ‘microbiome’, is aided by the development of non-culture-dependent DNA sequencing. It is increasingly apparent that the balance of microbial species greatly affects the health of the host. Disturbances in the composition of bacterial communities have been shown to contribute to various disease states, and there is a growing body of evidence that the vaginal microbiota, which is unique to each woman, plays an important role in determining many facets of reproductive health. The purpose of this review is to investigate what is currently known about the composition of the vaginal microbiome, including what is considered ‘normal’ in terms of bacterial species and abundance. We will investigate the impact of vaginal microbiome composition on reproductive outcomes within the context of infertility treatments, and the implications this has been shown to have on assisted reproductive technology procedures.