Objective. This study examines whether women's electoral fortunes in Australia have improved in line with changing social norms over the past century. We use new strategies to explore whether female candidates face discrimination by the voting public, or by political parties' preselection systems.

Methods. Using data from all elections to the House of Representatives between 1903 and 2004, we examine the relationship between candidates' gender and their share of the vote. We consider the electoral performances of female independent candidates, female incumbents, and female candidates from the Australian Labor Party (after 2001) in order to determine whether the bias against female candidates is driven by voters or preselectors. We also make use of gender pay gap and attitudinal data to examine how the ballot box penalty has shifted in line with changing social norms.

Results. We find that the vote share of female candidates is 0.6 percentage points smaller than that of male candidates (for major parties, the gap widens to 1.5 percentage points), but find little evidence that the party preselection system is responsible for the voting bias against women. Over time, the gap between male and female candidates has shrunk considerably as a result of changes in social norms (as proxied by the gender pay gap and attitudinal data) and the share of female candidates running nationwide.

Conclusions. A statistically significant gender penalty has been a consistent feature of Australian federal elections since 1903. The penalty against female candidates has narrowed since the 1980s, and this bias lies with the voting public rather than with the political parties themselves. We find little evidence that party-based affirmative action policies have reduced the gender penalty against female candidates.