Tamoxifen is a selective oestrogen receptor modulator (SERM). SERMs act on oestrogen receptors to inhibit oestradiol mediated negative feedback on the hypothalamic-pituitary-gonadal (HPG) axis, thereby upregulating gonadotrophin secretion and release from the pituitary. Hence, Tamoxifen is used to upregulate activation of the HPG axis in the treatment of male-factor infertility. However, due to a lack of robust evidence, Tamoxifen has not been FDA approved for use in male-factor infertility and so its use is currently off-label. In this study, we performed a literature search of the OVID medline database and identified 37 studies describing the effects of tamoxifen which we then reviewed. Evidence suggests Tamoxifen effectively increases androgen levels and sperm concentrations in males with idiopathic oligozoospermia. Evidence for increased motility and pregnancy rates in these patients is less conclusive. Further randomised control trials are needed to elucidate the safety of Tamoxifen combination therapies and their efficacy in improving pregnancy rates.