The relationship between parties and interest groups is vital to representative democracies, yet it is unclear whether gender composition influences their interactions. This study explores whether lobby groups with specific gender compositions engage more with certain political parties, potentially leading to a bifurcation in party-interest group relations. This issue is notable in light of the “modern gender vote gap,” which suggests that women tend to lean more towards the left. Using a novel dataset of 680 EU interest organizations, the study examines the dyadic relationships between lobbying teams and EU party groups through multiple regression analysis. It aims to uncover how gender composition and ideology shape these interactions, shedding light on biases that influence democratic representation. By addressing this gap, the research provides key insights into the the role of gender and ideology in interest group-party interactions, and how biases affect representative democracy.