The SEO is a member of:
- EVALNET (Evaluation network of the OECD DAC)
- EUHES (network of evaluators of the EU Member States)
- the DACH group (network of German language evaluators)
- the SWEP (Wallonia Evaluation and Foresight Society)
- the VEP (Vlaams EvaluatiePlatform)
It also follows the work of NONIE (Network of Networks on Impact Evaluation) and the European Evaluation Society (EES).