This paper proposes a decision-making tool for both supply firms and policy makers to evaluate the alignment between supplier’s knowledge and knowledge management systems (KMSs), and identify the level of efficiency and effectiveness of KMSs. Starting from these indices of efficiency and effectiveness, a taxonomy able to encompass the possible typologies of suppliers was established. A fuzzy logic-based decision-making tool is proposed to evaluate the efficiency and effectiveness of knowledge management systems in relation to a supplier’s knowledge. The proposed methodology is divided into three phases. The first phase consists in mapping supplier’s knowledge according to the two perspectives of analysis proposed by Nonaka in 1994. The second phase consists in mapping the KMSs used by suppliers by means of a Delphi panel involving two senior IT consultants and two researchers. Finally, the indices of efficiency and effectiveness are defined in the third phase. The paper evidences that suppliers adopt a large variety of KMSs to support the process of knowledge management. It seems to be of less concern that suppliers have scarce human and financial resources to invest in the area of knowledge management. This could be the result of the process of innovation in the field of information and communication technologies (ICTs) that are increasingly offering suppliers new low-cost opportunities (not requiring significant financial investments) and ease-of-use (needing no specific skills). The results of this paper suggest that the problem lies in the misalignment of the supplier’s knowledge with the KMSs adopted. In the end, the problem does not lie in difficulties in investing in human and financial resources, but in the ability to invest in the specific KMSs better able to support the KM process. This paper provides an operational tool for both suppliers and policy makers. Concerning the suppliers themselves, the proposed methodology may be used as a decision-making tool to suggest suitable changes in the adoption of KM-Tools and KM-Practices in order to increase the level of alignment with knowledge and thus improve the process of knowledge management. For policy makers, however, the methodology proposed here may be of help in identifying the weaknesses of the suppliers and identifying specific policies to support the competitiveness of supply systems by improving their management processes and the circulation of knowledge in a supply chain facing digital transformation.