In most organizations, promotions often require self-nomination and competition among applicants. However, research on gender differences in preferences for competition suggests that this process might result in fewer women choosing to participate. We study whether changing promotion schemes from a default where applicants must opt in (i.e., self-nominate) to a default where applicants must opt out (i.e., they are automatically considered for promotion, but can choose not to be considered) attenuates gender differences. In our first experiment, although women are less likely than men to choose competitive environments under the traditional opt-in framing, in the opt-out system both women and men have the same participation rate as men in the opt-in system. The increase in participation of women into competition is not associated with negative consequences on performance or well-being. In our second experiment, we show that opt-out framing does not entail penalties from evaluators making decisions about whom to hire. These results support the promise of choice architecture to reduce disparities in organizations. More generally, our findings suggest that gender differences in attitudes toward completion may be context-dependent. [Funding for this research was provided by University of Toronto Rotman School of Management's Institute for Gender and the Economy (GATE) and Behavioural Economics in Action at Rotman (BEAR).]