The androgen receptor is expressed in most breast cancers, more so than the estrogen receptor. There are many available drugs that modulate androgen receptor activity and are approved for use in humans, but how best to target this receptor in different disease contexts has been an issue fraught with controversy. We recently provided compelling evidence that the androgen receptor acts as a tumour suppressor in estrogen receptor positive breast cancer and that androgen receptor agonism is the best therapeutic strategy at early and advanced stages of disease. Androgen receptor agonists were effective alone or provided added benefit when administered in combination with standard-of-care therapies. The next challenge is to resolve the role of androgen receptors in different sub-groups of estrogen receptor negative breast cancer (e.g. HER2+, TNBC) to advance a rational basis for use of androgen receptor agonists or antagonists. Preliminary data suggests that in some contexts, the androgen receptor sustains a tumour suppressive role in estrogen receptor negative breast cancer.