An important line of research using laboratory experiments has provided a new potential reason for gender imbalances in labour markets: men are more competitively inclined than women. Whether, and to what extent, gender differences in attitudes toward competition lead to differences in naturally occurring labour markets remains an open question. To examine this, we run a natural field experiment on job-entry decisions where we randomize almost 9000 job-seekers into different compensation regimes. By varying the role that individual competition plays in setting the wage and the gender composition, we examine whether a competitive compensation regime, by itself, can cause differential job entry. The data highlight the power of the compensation regime in that women disproportionately shy away from competitive work settings. Yet, there are important factors that attenuate the gender differences, including whether the job is performed in teams, whether the position has overt gender associations, and the age of the job-seekers. We also find that the effect is most pronounced in labour markets with attractive alternative employment options. Furthermore, our results suggest that preferences over uncertainty can be just as important as preferences over competition per se in driving job-entry choices.