Design museums hold much power and potential to support design in contributing to the development of more just futures. However, they currently not only overrepresent the group of white, male, heterosexual star designers. They also often give a platform to problematic designs without thematizing their involvement in oppressive structures. This research project believes that, instead of improving design museums, transformational processes towards more just futures need to be explored. Since feminism is a powerful movement that revolves around such transformational processes, this thesis proposes to identify feminist tactics. The question is: Which feminist tactics could support transformational processes of design museums aiming towards more just futures? To explore this question, different theories and methods from both design research and feminist research are combined, like intersectionality, matters of care, terraforming, queer phenomenology, workshops, patchworking, museum visits, and visual analysis. The thesis proposes to learn feminist tactics from social movements like ACT UP and activist spaces like the Lesbian Herstory Archives, and also formulates characteristics and qualities of potential alternative design museums, that could then contribute towards the development of design justice.