Although women account for half of the Australian population (50.7%), women’s political representation in the federal parliament is low by world standards. Gender balance in political representation is an important goal of governments, yet Australia is ranked 50th in the world down from 15th in 1999 for female political representation (Sawer 2013; Inter-Parliamentary Union, 2018). Women hold only 29% of the Federal House of Representative seats (Parliament of Australia 2017). This is further complicated by the fact that, of the two major political parties, only the Australian Labor party has enforced gender quotas, the governing Liberal Coalition does not, instead preferring voluntary targets. While political scientists have investigated institutional and media bias against female politicians, less is known about how internalised gender biases structure voters’ attitudes towards female politicians. This form of discrimination is damaging yet difficult to measure as individuals may be unaware of their internalised bias. To redress this challenge, this paper applies experimental methods of randomly assigning respondents to a vignette about a politician that manipulates the politician’s gender. This method addresses the research questions: do Australians perceive female politicians as less competent and capable in their jobs? If so, what are the mechanisms through which this discriminatory bias is exhibited? This paper measures gender bias in Australians’ attitudes towards female politicians and applies multiple regression analysis to identify the determinants that trigger gender bias to redress gender inequality in the Australian parliament.