The Deventer System, or Dutch classification system for medieval and post-medieval ceramics and glass, is a method of categorising medieval pottery and glass, and is widely used in the archaeology in the Netherlands and Belgium. A 1989 publication about the city of Deventer first used this method, and since then it has been known in the Netherlands as the Deventer System. As of 2022, the database contains more than 26,000 objects (with accompanying drawings and/or photos) from more than 400 publications. To ensure consistency, the editors check the type numbering and issue new numbers as required.

The Deventer System is in Dutch, although a terminology sheet on fabrics and the applied features has been translated into English. More content will be translated into English, but to make the entire dataset bilingual is an enormous task and will take time.