Owing to global importance given to sustainability, commercial and government organizations alike are becoming aware about the need for them to implement sustainable supply chain management (SSCM) practices. These practices are mostly inter-organizational in nature, which introduce complexity due to the need for managing activities and information across the supply chain. However, currently there is still a lack of studies assessing the required organizational capability for implementing SSCM practices. Therefore, in this research-in-progress paper, we propose a SSCM capability maturity framework and provide an initial evaluation of the proposed framework through an in-depth case study with a large Australian city council. The framework together with the supportive empirical evidence represents a contribution to theory and practice. For practice, it helps organizations to understand their current SSCM maturity level and establish an appropriate strategy to progress in their maturity level. For theory, the study contributes to the on-going conceptual development related to SSCM and has clear implications for understanding the roles of IS/IT in building the required SSCM capability.