In modern democracies, political parties are the vehicles through which new groups gain political entry. Are parties equally welcoming to all new activists, irrespective of their ethnicity? In a field experiment, we study the responsiveness of local party officials in Sweden who are being contacted by fictitious individuals who want to become active in the party. We find that party officials are more likely to respond, and give informative answers that use a warmer and more welcoming tone, when they are being contacted by an individual with a Swedish name than by an individual with an Arabic name. These discriminatory effects are mainly found when contacting parties on the rightmost end of the political spectrum but are unaffected by appeals to electoral gain, common ideology, and norms of democratic inclusion. Given the importance of parties as gateways into politics, our findings have troubling implications for equal representation.