This paper extends the debate about redressing persistent gender inequality in Australia by examining the relationship between labour productivity and the wage gap in all states and territories (1986-2013). It is a critical case study as Australia's widening gender wage gap is contrary to other developed nations. Using four different estimation methods, we find that reducing the gap by 10% can boost per capita output up to 3%. To check the robustness of our findings, we also control for the effects of both physical and human capital. Our results suggest there exists a strong business case for eliminating the gender wage gap. Given the tangible benefits to both equity and efficiency, such a goal should be of paramount importance for policy makers.