Manipulation of the hormone oestrogen has been used for decades to treat hormone-dependent breast cancer. Currently, aromatase inhibitors (AIs) are used as first-line therapy against early and metastatic breast cancer in post-menopausal women. Despite these advances, several patients eventually experience a relapse of breast cancer and declined clinical response to treatment. As per recent findings, steroid sulfatase (STS) has emerged as a novel therapy target. This review aims at summarising the emerging field of STS inhibitor development and highlighting current findings from pre-clinical and clinical trials. The recently-developed dual-targeting compounds, such as dual aromatase-sulfatase inhibitors (DASI), have shown encouraging preclinical results and represent important new treatments for hormone-dependent breast cancer.