Transdisciplinary Sustainability Science has emerged as a viable answer to current sustainability crises with the aim to strengthen collaborative knowledge production. To expand its transformative potential, we argue that Transdisciplinary Sustainability Science needs to thoroughly engage with questions of unequal power relations and hierarchical scientific constructs. Drawing on the work of the feminist philosopher María Puig de la Bellacasa, we examine a feminist ethos of care which might provide useful guidance for sustainability researchers who are interested in generating critical-emancipatory knowledge. A feminist ethos of care is constituted by three interrelated modes of knowledge production: (1) thinking-with, (2) dissenting-within and (3) thinking-for. These modes of thinking and knowing enrich knowledge co-production in Transdisciplinary Sustainability Science by (i) embracing relational ontologies, (ii) relating to the ‘other than human’, (iii) cultivating caring academic cultures, (iv) taking care of non-academic research partners, (v) engaging with conflict and difference, (vi) interrogating positionalities and power relations through reflexivity, (vii) building upon marginalised knowledges via feminist standpoints and (viii) countering epistemic violence within and beyond academia. With our paper, we aim to make a specific feminist contribution to the field of Transdisciplinary Sustainability Science and emphasise its potentials to advance this field.