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Onno Ydema focuses his practice on litigation and corporate law, with an emphasis on international arbitration and cross-border litigation. His clients range from mid-size to large (internationally and locally operating) companies active inter alia in information and communication technology, as well as in the engineering and construction industries. Onno is a well-known author on divorce law, engaged by some of the top 500 wealthiest industry leaders in the Netherlands. Onno is also active as a part-time judge in the Court of Appeals in The Hague.


  • Commercial dispute resolution (litigation and arbitration)
  • Litigation
  • International and national arbitration
  • Corporate law
  • Mergers and acquisitions
  • Family law



  • Represented a Russian steel factory and its prime shareholders in a dispute with an off-shore company in the British Virgin Islands.
  • Represented an international company active in engineering software for Geographic Information Systems in an M&A project and in contract law issues.
  • Represented a company active in the development and distribution of software for the processing of data by major energy companies in the Netherlands, and for national and international governmental organizations in corporate law issues including contract law, intellectual property rights and M&A projects.
  • Represented an international company active in the development of software for data management by commercial organizations in a contract dispute.
  • Represented two companies developing software for health care information systems in a number of corporate law issues and litigation proceedings.
  • Represented a company developing heating systems for commercial and domestic appliances, and its shareholders.
  • Represented a company active in the installation of air conditioning and heating systems for major building projects in the Netherlands in corporate law issues and multiple litigation proceedings.
  • Represented an internationally operating U.S. pharmaceutical company in a major dispute with another international pharmaceutical industry over food additives.
  • Represented an internationally operating company developing and selling diagnostic systems for cancer treatment in, amongst others, a dispute with a U.S.-based biopharmaceutical company focused on the development and marketing of novel health care products and predictive medicine products.
  • Represented an internationally operating research company in a real estate dispute.
  • Represented a national company active in the development of software for data processing for major commercial and semi-governmental real estate and housing development organizations for contract disputes and corporate law issues.
  • Represented an international UK-based company developing educational programs for management training in a dispute with a distributor in the Netherlands.
  • Represented a national contracting company in litigation and corporate law issues.
  • Represented a number of investors in a major real estate development project in France in litigation proceedings related to guarantees.
  • Represented a company introducing Chinese telecom companies in the EU and EU companies in China.
  • Represented accountants (GPAs, Register- en AA-accountants) in liability cases, both in civil law disputes and in disciplinary proceedings (Raden van Tucht).
  • Represented (statutory) directors of companies in liability disputes.
  • Represented captains of industry for estate planning via international trusts and foundations.
  • Represented captains of industry for family law issues (litigation and mediation in divorce cases, etc.).

Recognition & Leadership

  • Team Member, a Law360 "Real Estate Practice Group of the Year," 2011 and 2022
  • Member, Winning Team, Chambers USA Award for Excellence, Real Estate, 2010 and 2017
  • Visiting-Professor, Law Department of the Erasmus University in Rotterdam, 2003-2013
  • Hon. Judge, Court of Appeals in The Hague, 2002-Present
  • Fellow, Dutch Meijers Institute for Legal Research, 2001-Present
  • Editor, Yearbook on Divorce Law for Judges and Attorneys, 1997-Present
  • Professor, Law Faculty of the University of Leiden, 1997-2014
  • Member, Dutch Bar Association


  • LL.M., University of Leiden, Netherlands
  • D.Litt, University of Leiden, Netherlands
  • Ph.D. (LL.D.), University of Leiden, Netherlands
  • The Netherlands
˘ Not admitted to the Dutch Bar.
  • Dutch, Native
  • English, Fluent
  • French, Conversational
  • German, Fluent