<p>This article analyses the novel humanitarian responses originating in Poland to assist Ukrainian refugees and the Ukrainian war effort. We argue that since February 24, 2022, the commitment by citizens and nongovernmental organizations (NGOs) providing support to refugees and to people in Ukraine demonstrates the crucial role of local actors and grassroots engagement in complex humanitarian crises. New forms of cooperation, which cut across previous divides, or what we call ad-hoc, needs-based partnerships (ANP) represent an important evolution in grassroots activism but also in global humanitarian assistance. Moreover, some ANPs go beyond providing traditional humanitarian aid by crowdfunding to purchase and deliver equipment for the Ukrainian military. These initiatives blur previous distinctions of humanitarian aid and demonstrate the untapped self-organizational potential of civil society. The paper concludes by calling for an effort to continue incorporating the voices of Ukrainian, other non-Western and non-European scholars in studies of humanitarian assistance.</p>