The paper aims to develop Lean Manufacturing (LM) maturity criteria for assessing the level of LM implementation in Tanzania. The criteria will assist to determine LM maturity for manufacturing organizations in the country, which at the moment is not known. The study used survey and purposive sampling techniques to collect responses from 243 responses. Structured questionnaires and interviews were used in collecting responses from various respondents. Descriptive statistics through SPSS and the Fuzzy Analytical Hierarchy Process (FAHP) were used to analyze the data. The study has revealed the elimination of waste, continuous improvement, just-in-time, multifunctional teams, information systems, and zero defects as lean performance criteria for manufacturing industries in Tanzania. FAHP weights indicated that the criteria have different weights based on the level of manufacturing organizations. For micro industries, the FAHP weights of the criteria are the elimination of waste (0.2), continuous improvement (0.11), zero defects (0.26), just in time (0.31), multi-functional teams (0.04), and information systems (0.07). The FAHP weights can be used by the manufacturing organizations in setting strategies for improving the maturity level for each size of the manufacturing organizations. Improvement in maturity level will lead to improvement in organizational performance of manufacturing organizations. Better performance of manufacturing organizations will have positive contributions to the country’s Gross Domestic Product (GDP).