Much of Europes response to refugee arrivals since 2015 has involved grassroots volunteers, with a marked absence of traditional humanitarian organisations. Although professional organisations and governments eventually took the lead in some countries, the ad hoc response was, and continues to be, hugely significant. The role of these organisations and the challenges they encounter on the Greek islands remains under-reported, with notable gaps in academic documentation of the perspectives of those involved. This project employs a qualitative research approach to analyse the grassroots humanitarian response to refugee arrivals in Chios since 2015. Through semi-structured interviews with long-term volunteers and organisation founders, this study documents how the response (built initially on principles of solidarity and humanity) has evolved. It explores the development of the grassroots organisations involved, and their interactions with other humanitarian actors. While grassroots actors in Chios are collaborating more than ever with each other, many have increasingly difficult interactions with the authorities. To speak out risks losing access to the refugee population. Frustration is growing as humanitarian efforts are constantly undermined by complex government restrictions and bureaucratic obstacles. The political economy of humanitarian responses now faces a constant disruption of activity by host governments in Europe as part of a strategy to discourage both migrants and humanitarians themselves, by wearing them down and creating barriers to the delivery of appropriate and effective aid. This case study shows the constant need for reorganisation of responses by these new humanitarians as dealing with government authorities becomes ever more difficult.