ProfessorCathryn Costello

Cathryn Costello is Full Professor of Global Refugee and Migration Law at the Sutherland School of Law, University College Dublin, where she is also Director of the PhD Programme. She was formerly Professor of Fundamental Rights and Co-Director of the Centre for Fundamental Rights at the Hertie School (2020 – 2023).. She was Andrew W Mellon Professor of International Refugee and Migration Law at the Refugee Studies Centre, University of Oxford (2013-2023). She remains a Visiting Professor at both the Hertie School and the University of Oxford. 

She is a leading scholar of international and European refugee and migration law and also explores the relationship between migration and labour law in her work. She is the author of The Human Rights of Migrants and Refugees in European Law (OUP 2015) (co-winner of the Odysseus Prize 2016) and is currently completing a monograph examining refugee recognition practices globally, as well as a short critical introduction to international refugee law. She is the co-editor of the Oxford Handbook of International Refugee Law (co-editors Michelle Foster and Jane McAdam) (OUP 2021) and Migrants at Work: Immigration and Vulnerability in Labour Law (co-editor Mark Freedland) (OUP 2014), a ground-breaking work on the impact of immigration law and status in labour relations. Her most recent collaborative volume was IOM Unbound: Obligations and Accountability of the International Organisation for Migration in an Era of Expansion (co-editors Megan Bradley & Angela Sherwood) (Cambridge University Press, June 2022), examining legal and political accountability of this IO across its diverse areas of activity.

She was the Principal Investigator of RefMig, an ERC-funded research project exploring refugee mobility, recognition and rights (2018-2024), and currently leads the Volkswagen Foundation funded AFAR (Algorithmic Fairness for Asylum Seekers and Refugees) project. She has also undertaken research for UNHCR, the Council of Europe and the European Parliament. She holds a doctorate in law from the University of Oxford. She was recently awarded a ERC Consolidator grant for RefLex: Is International Refugee Law Effective? (to commence in September 2025), a large comparative study on the effectiveness of this body of law, in particular exploring the role of legal mobilisation in its impact. 

She has supervised 7 doctorates to completion, and examined over 20 across the globe, on a wide variety of topics in global refugee and migration law. Her supervisees are now successful academics, or are working in leading legal practices or advocacy organisations. She has also supervised dozens of masters’ theses, many of which were published.

She has also successfully mentored a Marie Curie grantee, Dr (now Professor) Grazyna Baranowska. She welcomes approaches from outstanding graduates wishing to undertake doctorates or postdoctoral work in global refugee and migration law.  (See below for. a spring 2025 webinar on the Marie Curie Postdoctoral Action).

Current Doctoral Supervisee:

Vera Wriedt, Hertie School, Bordering Belonging: Colonialism, Nationality and Expulsions in the European and African Human Rights Systems (Other supervisors: Professor Marie-Benedicte Dembour, University of Ghent; Professor E Tendayi Achiume, UCLA) (2020-2025).

Her former doctoral supervisees:

Francesco Bosso, The Borders of the Rechtsstaat: Migrant Exclusion and the Constitutional State in post-crisis Germany (ODID, co-supervised with Professor Ruben Andersson, 2018-2022), examined by Professors Lucia Zedner and Antje Ellerman.  No corrections, Jan 2022. 

Current Role:  Rechtsberater*in (legal adviser); Kontakt- und Beratungsstelle für Flüchtlinge und Migrant_innen e. V., Berlin.

Emilie McDonnell, Protecting the Right to Leave in an Era of Externalised Migration Control, co-supervised with Associate Professor Miles Jackson, examined by Professors Guy S Goodwin-Gill and Vincent Chetail. 2021.

Current Role: Policy Officer, Human Rights Watch, London.

Lauren Nishimura, Climate Change, Human Rights, and Adaptive Mobility, co-supervised with Professor Catherine Redgwell, examined by Professors Lavanja Rajamani & Jane McAdam. No corrections. 2021.

Current Role:  Lecturer, Melbourne Law School, University of Melbourne (from 1 January 2025).

Yulia Ioffe, The Rights of Asylum Seeking Children: Integrating the Child's Best Interests Principle through Interpretation, co-supervisor Eirik Bjorge, examined by Professors Catherine Redgwell & Michelle Foster. No corrections, 2020.

Current role: Associate Professor in Humanitarian Law and Human Rights, University College London, Institute for Risk and Disaster Reduction. 

Catherine Briddick, Migration Status and Violence Against Women: Four Legal Responses Evaluated, examined by Professors Sandra Fredman & Siobhan Mullally.  No corrections, 2019.

Current role: Andrew Mellon Associate Professor of International Human Rights and Refugee Law, Refugee Studies Centre, ODID, University of Oxford.

Rowena Moffatt, An Appeal to Principle: A Theory of Appeals and Review of Migration Status Decision-Making in the United Kingdom, examined by Professors Guy S Goodwin-Gill and Robert Thomas. 2016.

Current role: Barrister, Doughty Street Chambers, London.

Mimi Zou, The Legal Construction of Migrant Work Relations: Precarious Status, Hyper-Dependence and Hyper-Precarity (co-supervised with Professor Mark Freedland), examined by Professors ACL Davies & Judy Fudge.  No corrections, 2014.

Current role: Head of School and Professor of Law, School of Private and Commercial Law, Faculty of Law and Justice, UNSW Sydney.