The representation of gender and sexual diversity should be an important priority for any socially engaged museum today. Currently, activists and interest groups such as Queering the Collections are working to push this agenda within museums in the Netherlands. This short essay contributes to these attempts by addressing the importance of the terminology museums use to represent gender and sexual diversity. What are the terms that people use to describe their own identities and how have these changed over time? How do these terms differ from those museums have used? What kind of politics of inclusion or exclusion has influenced the emergence of these terms? And how can museums contribute to ongoing attempts to achieve equality?