A debate about emerging models of urban living labs (ULLs) 2.0 is taking place in the literature, highlighting the importance of social aspects. The aim of this paper is to examine feminist ULLs as a potential source of social sustainability. This is conducted through a case study of a feminist ULL in Sweden, where girls and young women, together with multiple professional stakeholders, used Minecraft to redesign a public square in their neighbourhood - a marginalised suburban area of Stockholm. Data was collected through participant observations of six experimental labs during 1 year, surveys of the ULL participants, and an analysis of the final Minecraft designs. The empirical findings reveal a process of mutual learning between girls and professional stakeholders, where the girls were viewed as place experts. The findings also reveal that the girls’ visions include a socially sustainable transition of the urban square: from patriarchal to inclusive, from grey to green, and from a transit area to a meeting-place. There were some differences between girls and professional stakeholders. Whereas the professionals tended to emphasise security in their visions, the girls emphasised liveability. Although more research is needed, this paper concludes that feminist ULLs can be a possible source of social sustainability. However, the ULL process must both be inclusive, and at the same time unlock long-term transformation in the physical environment.