Members of the research group participate in several international research groups and collaborations including:

The Common Core of European private Law (Trento Project)
The aim of this project is to establish common rules with respect to certain fields of private law of the different members of the European Union, although their methods of research are totally different.

Follow-up of Co-PECL
The Joint Network on European Private Law (Co-PECL) has been concluded and will be followed up by some projects that are currently considered (may be a European Law Institute?).
Several members of the CSECL have been involved in drafting the CFR whose efforts have resulted in the Draft Common Frame of Reference (DCFR), Outline Edition, which appeared tin 2009. The CFR will most likely lead to a non-binding instrument, which will be the basis for the future development of Community legislation, including possibly the formal enactment of an (optional) Civil or Contract Code.

The Study Group on Social Justice in European Private Law
Finally, within the Social Justice Group CSECL researchers co-operate with researchers of the Paris I, the London School of Economics, the European University Institute (Florence), the University of Helsinki, ZERP (Bremen), the Karl-Franzens-Universität Graz and the University of Catania. This group conducts common research of social justice and regulatory legitimacy within the European Contract Law. 

The Ius Commune Research School
CSECL co-operates with the Faculties of Law of the University of Utrecht, the University of Maastricht,  the Catholic University Leuven (Belgium) and with individual researchers of the University Stellenbosch (South Africa), the University of Edinburg (Scotland), the Free University in Amsterdam, Tilburg University and the Erasmus University Rotterdam.

Moreover, CSECL is partner of the Finnish Centre of Excellence in the Foundations of European Law and Polity Research.

Furthermore, there are numerous international collaborations on an individual basis with scholars from many leading European and American universities including Harvard, EUI, LSE, Oxford and Sciences Po.

Locally, the CSECL collaborates with other academics within the Faculty of Law itself and outside the Faculty, especially with the Amsterdam Centre for Law and Economics (ACLE), through joint research projects and seminars.