Businesses and policymakers are paying increased attention to diversity and inclusion within organizations. However, evaluating progress towards these goals is challenging because diversity is a subjective measure, influenced by individuals’ traits, beliefs, and values. Across three studies (total N = 1601), we found that feminist ideology affects diversity evaluations, such that (1) ideologues are more likely to include in their definition of gender diversity an element of rebalancing the imbalance between women and men (r = .49), (2) people with stronger (vs. weaker) feminist ideology evaluated all-men groups to be less diverse than all-women groups (Study 1 d = -.31; Study 2 d = -.25) and (2) under a diversity mandate, ideologues reported greater differences between the diversity of all-men and all-women groups (d = -.55). Thus, we observe that feminist ideology influences evaluations of diversity, and suggest this is the case because ideologues have different reference points for what constitutes a diverse group. Additionally, we learn that organizations signaling congruency between their and ideologues’ views via mandates encourages feminists to report even greater differences in the diversity of all-men and all-women groups. Thus, when employing diversity mandates, organizations may exacerbate differences in diversity perceptions amongst people who hold greater versus weaker feminist ideology.