Background: The issue of managing sustainability in supply chain seems to be more and more complex. There are many aspects that need to be taken into consideration when planning, implementing and monitoring environmental and social conditions of supply chains. Despite many works, already published, on the concept of sustainable development (SD) is seems that the issue of assessment and especially the issue of maturity in the light of the SD concept is still not developed enough. Methods: The general aim of the paper is the analysis of the maturity issue in the context of sustainability. The main objective is to conceptualize the idea of maturity in sustainable supply chain. Beside the literature research the own proposition of theoretical model was described. Results: The article describes the issue of maturity as an element of managing sustainable development in the supply chain. The author presented a theoretical model of the maturity. Moreover the author gave some recommendations how to manage the sustainability issues in supply chain in more mature approach and introduced some useful tools among which are: certification, code of conduct and code of ethics, audits, projects etc. Conclusions: The issue of maturity seems to be very useful for proper understanding the idea of sustainable development in supply chain. The developed model can be used as self-assessment method to check at which level of implementation the idea of SD is analyzed in supply chain. Furthermore, the next phase of the planned research in form of practical verification of the model was advised as well as a research of identification of new factors and tools in analyzed area.