The ISSP offers 5 levels of membership:
- Student – available to students for one year at a discounted rate
- Member – available for anyone with an interest in Six Sigma, but particularly designed for Green Belts who wish to develop further
- Professional – Six Sigma Black Belts who have met the criteria of the ISSP assessment process
- Fellow – Six Sigma Black Belts who are making a significant contribution to the world of Six Sigma will be invited to join as Fellows
- Affiliate – Organisations who wish to access the ISSP, contribute to the network and offer services to members.