Abstract: | Contagion theory, one of the most appealing explanations of women’s representation, posits that when small parties start actively promoting women candidates, larger parties will be incentivised to follow suit and contagion will eventually spread throughout the party system. In examining the diffusion of gender quotas in Spain and Portugal, this article revisits contagion theory and adopts a more comprehensive approach. The results suggest that diffusion is better captured when one takes into account that political parties not only react to electoral competition but also adapt to policy innovation through learning and emulation, whose effects are often shaped by intra-party factors. |