Terry Gill is Emeritus Professor of Military Law at the University of Amsterdam having held the chair from September 2001 until September 2020 and was also holder of the chair in Military Law at the Netherlands Defence Academy from 2005 until July 2019. He was also firstly Assistant and later Associate Professor of Public International Law at Utrecht University from 1985-2013. He is founder and co-director of the Research Program on the Law of Armed Conflict and Military Operations (LACMO) at the Amsterdam Centre for International Law and is co- convenor of the Netherlands Research Forum on the Law of Armed Conflict and Peace Operations (LACPO) in which researchers within the LACMO program and external researchers and practitioners hold periodic meetings to discuss recent developments in the relevant areas of interest. He is also chair of the LACMO International Research Network which fosters and coordinates research cooperation in the areas of international military law and the law of armed conflict between a number of leading institutions in Europe, North America, Asia and the Pacific which are active in this field . Professor Gill was Editor in Chief of the Yearbook of International Humanitarian Law from 2012 -2021 and is a member of the editorial boards of the Journal of Armed Conflict & Security Law and the Journal of International Peacekeeping . He is a member of the Board of Directors of The International Society of Military Law & the Law of War and member of International Law Association, the Netherlands Society of International Law, and of the Netherlands Military Law Society (Militair Rechtelijke Vereniging).
He (co) teaches courses on international humanitarian law , international military operational law and the use of force at the University of Amsterdam and is currently (co) supervisor of six PhD candidates affiliated with ACIL and LACMO on various topics related to international military operational law, humanitarian law and the use of force. He has been a Fulbright visiting scholar at Columbia University and visiting research fellow at Cambridge University, Universidade de Coimbra, Universidad de Granada and the International Institute of Humanitarian Law in San Remo.
He was a member of the International Group of Experts which produced the Tallinn Manual on the Application of International Law to Cyber Warfare, which was published in 2013 and which was updated in 2017 to include the application of international law to peacetime cyber activities (Tallinn 2.0 Manual on the International Law Applicable to Cyber Operations). He was chairman of the Study Group of the International Law Association which completed a report on The Conduct of Hostilities in the 21st Century in 2017 and a senior academic advisor and co-editor/author of the Leuven Manual on the Application of International Law to Peace Operations which was prepared under the auspices of the International Society of Military Law & the Law of War and published in December 2017. He was a member of the expert group on "Direct Participation in Hostilities" convened by the ICRC and TMC Asser Institute between 2003-2008 and has contributed to several military manuals in use by the Netherlands armed forces and policy advice reports to the Netherlands Government and Parliament on matters of public international law. Professor Gill was named "Officer in the Order of Orange Nassau" in September 2019 in recognition of his contribution to legal education and research in support of the Netherlands armed forces.
Professor Gill's research is primarily in the areas of international law relating to the use of force ,international humanitarian law and military operational law. He has published numerous articles on these topics in both Dutch and English and as director of the research program Law of Armed Conflict and Peace Operations and the research forum LACPO, coordinates research in these fields by senior researchers and PhD candidates from ACIL, Netherlands Defence Academy, TMC Asser Institute and other organizations within the context of those fora.
Some recent and forthcoming publications include:
- Gill, T.D. " Some Reflections on the Threshold of International Armed Conflict and the Applicability of the Law of Armed Conflict in Any Armed Conflict" The Howard S. Levie Distinguished Essay 99 International Law Studies (2022) 698-730
- Gill, T.D. "The Jus ad Bellum and Russia's Special Military Operation in Ukraine" in 25/2 Journal of International Peacekeeping" (2022). 121-127
- Gill, T.D. "Reconciling the Irreconcilable: Some Thoughts on Belligerent Equality in Non-International Armed Conflicts" in 51 Netherlands Yearbook of International Law 2020 (August 2022), 343-360
- Gill, T.D. " Rethinking the Scope of Application of International Humanitarian Law and Its Place in the International Legal System" in V. Koutroulis & T. Ruys (eds.) 60 The Military Law and Law of War Review, Edward Elgar Publishers (2022), 58-70
- Gill,T.D. "The Jus ad Bellum anno 2040: An Essay on Possible Trends and Challenges" in M. Waxman & T. Oakley (eds.) The Future Law of Armed Conflict,Lieber Studies vol. 7, Oxford University Press (2022), 25-40
- Gill, T.D. "International Humanitarian Law Applied to Cyber Warfare: Precautions, proportionality and the notion of "attack" under the humanitarian law of armed conflict" in N. Tsagourias & R. Buchan (eds.) Research Handbook on International Law and Cyberspace (2nd rev. ed.) Edward Elgar Publishers (2021), 457-470
- Gill, T.D. " The Law of Belligerent Occupation; Disputed Territory and the Distinction between Invasion and Occupation" in A. de Guttry, H.H.G. Post & G.Venturini (eds.) The 1998-2000 Eritrea-Ethiopia War and Its Aftermath in International Legal Perspective, T.M.C. Asser Press/Springer Publishers (2021), 441-447
- Gill,T.D. and Tibori Szabo, K. "Twelve Key Questions on Self-Defence against Non-State Actors-and Some Answers" 50 Israel Yearbook of Human Rights , Brill/Nijhoff,167-205 (2020)
- Gill, T.D. and Tibori Szabo,K. "Twelve Key Questions on Self-Defense against Non-State Actors" 95 International Law Studies, 467 U.S. Naval War College (2019) https://digital-commons.usnwc.edu/ils/vol95/iss1/15/ SSN 2375-2831
- Gill, T.D. and Tibori Szabo, K. " The Intervention in Somalia- 1992-95 in T.Ruys, O. Corten and A. Hofer, The Use of Force in International Law: A Case Based Approach, Oxford University Press, 482-494 (2018)
- Gill,T.D. Entries on " Belligerents",State of Belligerency" , " Equality of Belligerents" and "Peacekeeping" in N. Pons & D. Dukic The IHL Companion , Brill Publishers (2018)
- Gill, T.D., Boothby, W., Fleck, D. and VanHeusden, A. Leuven Manual on the International Law Applicable in Peace Operations, Cambridge University Press (2017)
- Gill, T.D., Geiss, R and Heinsch, R. Final Report of the Study Group of the International Law Association on The Conduct of Hostilities in the 21st Century .published online on the ILA website and in 93 International Law Studies, 322 (2017) and in print in 19 Yearbook of International Humanitarian Law 2016 , TMC Asser Press/Springer Publishers, 287 (2017)
- Gill, T.D., Van Haaster, J & Roorda, M, "Some Legal and Operational Considerations Regarding Remote Warfare" in Jens David Ohlin (ed.) Research Handbook on Remote Warfare, Edward Elgar Publishers 298 (2017)
- M. .Schmitt ( ed.) Tallinn Manual 2.0 on the International Law Applicable to Cyber Operations Cambridge Univ.Press (2017)
- Gill, T.D. "Classifying the Conflict in Syria" 92 International Law Studies 353 (2016)
- Gill,T.D. "Some Considerations Concerning the Role of the Ius ad Bellum in Targeting" in P. Ducheine, M. Schmitt & F. Osinga (eds.) Targeting: The Challenges of Modern Warfare TMC Asser/Springer Press , 101 (2016)
- Gill, T.D.& Fleck, D. (eds.) The Handbook of the International Law of Military Operations 2nd,ed., Oxford Univ. Press (2015)
- Gill, T.D. "When Does Self-Defence End?" in M. Weller (ed.) The Oxford Handbook of the Use of Force in International Law, Oxford Univ. Press, 737 (2015)
- Gill, T.D. "International Law Applied to Cyber Warfare: Precautions, Proportionality and the Notion of 'Attack' under the Humanitarian Law of Armed Conflict" in N.Tsagourias & R. Buchan (eds.) Research Handbook on International Law and Cyberspace, Edward Elgar Publishers 366 ( 2015)
- Gill, T.D. "Some Thoughts on the Relationship between International Humanitarian Law and International Human Rights Law: a Plea for Mutual Respect and a Common Sense Approach" in Haek, Y. & Mc Gonigle Leyh, B. The Realisation of Human Rights: When Theory Meets Practice, Intersentia Publishers .333 (2013)
- Gill, T.D. & Ducheine, P.A.L. "Anticipatory Self-Defense in the Cyber Context" Vol. 89, 438 International Legal Studies of the US Naval War College (2013)
- Schmitt, M (ed.) The Tallinn Manual on the Application of International Law to Cyber Warfare, Cambridge University Press (2013)
- Gill,T.D., Marchand, C, Ducheine, P.A.L & Boddens Hosang, J.F.R, General Report to the 19th Congress of the International Society of Military Law & the Law of War on "Legal Interoperability and Ensuring Observance of the Law Applicable in Multinational Deployments" Vol. 19 Review of Military Law and the Law of War 121-172 (2013)
- Gill, T.D. "Chivalry: A Principle of the Law of Armed Conflict?" in Mathee ,M, Toebes, B. and Brus, M, Armed Conflict and International Law: In Search of the Human Face,33 (2013)
- Gill, T.D. and Tibori Szabo, K. The Use of Force in the International Legal System, Cambridge Univ. Press, expected publication July- Sept, 2023, approx. 350pp.
In addition to the teaching activities referred to above, Prof. Gill conducts frequent guest lectures and training sessions at universities inside and outside the Netherlands and at the Hybrid Threat Centre in Helsinki