Dr Maria Ioannidou, Counsel, is part of the Competition Law practice of our Firm. Maria is a Reader (Associate Professor) in competition law at the School of Law, Queen Mary, University of London, where she also serves as the Deputy Director of the Institute for Competition and Consumers. Maria holds a DPhil, MPhil, and MJur from the University of Oxford, and an LLM and LLB, both with distinction, from the University of Athens.

She has teaching, research, advisory, litigation and regulatory experience in all areas of EU and Greek competition law, with significant added experience in UK competition law. Having served as Commissioner Rapporteur and Member of the Board at the Hellenic Competition Commission, she has been involved in complex decision making while adjudicating numerous cases across different sectors of the economy including automobile, energy, transport, payment services, betting, consumer goods, and digital markets.

Maria also serves as the managing editor for the Journal of Antitrust Enforcement and as an editor of the World Competition Law and Economics Review. She is the author of ‘Consumer Involvement in Private Competition Law Enforcement’ (OUP 2015).

Academic Background

  • DPhil, University of Oxford
  • MPhil, University of Oxford
  • MJur, University of Oxford
  • LLM in civil law, University of Athens, distinction
  • LLB, University of Athens, distinction (valedictorian)
  • Erasmus scholar, Humboldt University, Berlin


  • Greek
  • English
  • German

Professional Memberships

  • Member of the Athens Bar Association
  • Member of the ASCOLA – Academic Society for Competition Law
  • Member of the Competition Law Scholars Forum (CLaSF)
  • Fellow of the Higher Education Academy



  • M Ioannidou, Competition Law Remedies in the Digital Economy (OUP, forth 2025)
  • M Ioannidou and B Xiong, Competition Law and Policy in Digital Markets: A Comparative Analysis in the EU and China (OUP, forth 2024)
  • M Ioannidou and D Mantzari (eds), Research Handbook on Competition Law and Data Privacy (Edward Elgar, forth 2024)
  • M Ioannidou, Consumer Involvement in Private EU Competition Law Enforcement (OUP 2015).


  • M Ioannidou, ‘Unpacking multi-level elements in digital markets: Informing effective enforcement and remedial design in EU competition law’ in Carlo Maria Colombo, Kathryn Wright, Mariolina Eliantonio (eds), The Changing Governance of EU Competition Law: a Constitutional Challenge? (Hart 2023 forth)
  • M Ioannidou, ‘ “Digital Agoraphobia”: exploitative abuses in digital markets’ in I Kokkoris (ed), Research Handbook in Competition Enforcement (Edward-Elgar 2022)
  • M Ioannidou, "Responsive Remodelling of Competition Law Enforcement" (2020) 40 Oxford Journal of Legal Studies 846
  • M Ioannidou and D Mantzari, "The UK Domestic Gas Electricity (Tariff Cap) Act: Re-regulating the Retail Energy Market" (2019) 82 Modern Law Review 488
  • M Ioannidou, "Compensatory Collective Redress for Low Value ConsumerClaims in the EU: A Reality Check" (2019) 6 European Review of Private Law 1367
  • M Ioannidou, “The Member State Reports on the Transposition of the Directive: Cyprus” in Barry Rodger, Miguel Sousa Ferro, and Francisco Marcos (eds), The EU Antitrust Damages Directive (OUP 2018) 82
  • M Ioannidou, “The Member State Reports on the Transposition of the Directive: Greece” in B Rodger, M Sousa Ferro, and F Marcos (eds), The EU Antitrust Damages Directive (OUP 2018) 158
  • M Ioannidou (with Ioannis Kokkoris), “Challenges in Competition Law and the Pharmaceutical Sector in BRICS Countries” in in P Figuerora and A Guerrero Perez (eds), EU Law of Competition and Trade in the Pharmaceutical Sector (Edward Elgar 2018) 687
  • M Ioannidou, “The Application of Article 102 TFEU in the EU Energy Sector: a critical evaluation of commitments” in F Di Porto and R Podszun (eds), Abuse Regulation in Competition Law (Edward Elgar 2018) 129
  • M Ioannidou, “Effective Paths for Consumer Empowerment and Protection in Retail Energy Markets” (2018) J Consum Policy https://doi.org/10.1007/s10603-018-9372-5
  • M Ioannidou and J Nowag, ‘Can two wrongs make it right? Reconsidering minimum resale price maintenance in the light of Allianz Hungaria’ (2015) European Competition Journal 340
  • M Ioannidou (co-authored with A Ezrachi), The Internationalization of Competition Law and Policy: The Domestic Perspective (2014) 1 The Journal of International and Comparative Law 39
  • M Ioannidou (co-authored with A Ezrachi), ‘Buyer Power in European Union Merger Control’ (2014) 10 European Competition Journal 1
  • M Ioannidou (co-authored with V Brisimi), ‘Stand-alone damages actions: insights from Greece and Cyprus’ (2013) 34 European Competition Law Review 654
  • M Ioannidou (co-authored with A Ezrachi), ‘Public Compensation as a Complementary Mechanism to Damages Actions: from policy justifications to formal implementation’ (2012) 6 Journal of European Competition Law and Practice 536
  • M Ioannidou, ‘Reforming UK Competition Law Regime: The Consumer Perspective’ (2012) 11 Competition Law Journal 28
  • M Ioannidou, ‘Enhancing Consumers’ Role in EU Private Competition Law Enforcement: a Normative and Practical Approach ’ (2012) 8 Competition Law Review 59
  • M Ioannidou (co-authored with A Ezrachi), ‘Access to Justice in European Competition Law – Public Enforcement as a Supplementary Channel for “Corrective Compensation’ (2011) 19 (2) Asia Pacific Law Review 1
  • M Ioannidou (co-authored with V Brisimi), ‘Criminalising Cartels in Greece: a Tale of Hasty Developments and Shaky Grounds’ (2011) 34 World Competition 157.

Thought Leadership

Maria has been invited to give evidence to the UK All Party Parliamentary Group on AI and has submitted written evidence to the House of Lords Select Committee on AI and European Union Committee. She is often invited to speak in national and international conferences.