a Malaysia Airlines Boeing 777 that had departed a few hours before from Amsterdam airport in the Netherlands was shot down near Donetsk in Ukraine with 298 people on board. None of them survived the crash. The Dutch government soon called for an independent investigation into the causes of the crash. The conditions for such an investigation were highly complex. The circumstances of the crash indicated criminal intent, and rumours were that the plane was shot from the sky. The International Civil Aviation Organization (ICAO) stipulates in its Annex 13 that an accident investigation needs to include the country where the crash took place (State of Occurrence), the State of Registry of the aircraft, the State of the Operator of the aircraft (the airline) and the State of the manufacturer of the aircraft. The Netherlands represented none of these states, but the majority of victims were Dutch citizens. The authorities of Ukraine, where the plane crashed, soon asked the Dutch Safety Board to take the lead in the investigation since the Dutch had established capacity to conduct such an investigation, and the Ukraine government was involved in a violent conflict with Russian separatists. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. Abstract Transboundary crises, incidents and disasters, such as chemical spills, airplane crashes and critical infrastructure breakdowns, involving multiple levels and domains of governance pose a particular set of challenges. These challenges also pertain to the investigation and learning phase of a crisis. We study a typical transboundary case: the crash of a Malaysia Airlines Flight 17 (MH17), with 298 people on board from a variety of nationalities but the majority from the Netherlands, that crashed in Ukraine in a conflict zone near the Russian border. The MH17 case contains valuable lessons on transboundary disaster investigations. The Dutch Safety Board (DSB) took the lead of the international independent investigation into the causes of the crash.With an international group of stakeholders, the DSB investigated a crash that resulted from a bilateral conflict, requiring the support from Ukraine's powerful neighbour Russia that meanwhile stood accused of withholding evidence and supporting Ukrainian separatists. Retrieving evidence and researching the causality of the crash was no easy task. If countries wish to follow their ambition to learn from accidents in order to "prevent the past repeated," they may more often need to investigate such transboundary cases. This case study probes into how challenges that are typical to transboundary crises affected the accident investigation into the MH17 disaster.We search for lessons on transboundary accident investigation that transcend the boundaries of this single case. Such lessons may prove invaluable for l...