The concept of circular economy (CE) has gained momentum in the construction industry to mitigate the effects of climate change and decouple economic growth from environmental impact. There is a growing body of research related to the circularity of specific construction materials, as well as to the entire building. However, there remains a lack of understanding at the construction product level, and this lack of transparency prevents informed decisions when choosing which products to use in projects and how those products support the CE. A maturity assessment is one methodology that can provide insights for both product decisionmakers and product suppliers. Maturity assessments are a way to evaluate the level of development or progress towards a certain goal, whether at the organization, project, or product level. This paper proposes a conceptual framework to assess construction product system circularity maturity. Through a systematic literature review, the authors analyze existing CE maturity assessments and CE indicators for construction products to develop the framework. The functional unit is defined as a construction product, which is defined as an integrated system with multiple materials (i.e. a prefabricated wall system). This research finds that while there are many CE assessment frameworks for the construction sector, these must be translated into a construction product context, which requires a tailored subset of circularity indicators and maturity levels. The paper proposes construction product maturity levels ranging from "initial" to "optimizing" for key circularity indicators at the construction product level, including, material procurement, manufacturing, product use phase, and end-of-life. This conceptual framework serves as a practical tool for decisionmakers and as an educational tool for suppliers on how to support the CE in construction.@en