Brazilian small and medium-sized companies (SMEs) face several limitations in the implementation of cleaner production (CP). These limitations unfavourably affect their sustainable transitions. For SMEs to achieve sustainable changeovers, it is essential to implement changes in their production systems by adopting CP in principle and in practice. A literature review indicated that no previous work assessed the barriers to implementing CP in industrial SMEs belonging to the metal-mechanical sector, highlighting a gap requiring additional research. Hence, the objective of this paper was to propose a framework for overcoming obstacles to the implementation of CP for small and medium-sized companies. For that purpose, four related propositions were identified in the literature by means of a systematic review. These propositions assert that SMEs should identify the barriers to implementing CP and use tools to prioritize the identified hurdles and the main actions required to implement CP. In addition, they propose that the lack of investment capital in SMEs enhances the barriers and that the higher the return on investment is, the higher the probability is that an SME adopts CP. Those propositions were validated through multiple case studies comprising four industries belonging to the Brazilian metal-mechanical sector. The cases were small or medium-sized companies that had not yet implemented CP but had manufacturing processes with CP implementation opportunities. The results of the case studies yielded a novel solution to support SMEs in overcoming barriers to implementing CP, providing a contribution to CP theory. This consists of the utilization of a framework with four simple and friendly steps to be used by managers and employees, providing a contribution to CP practice. It is relevant to note that this framework relies on possible economic gains that SMEs can obtain with the adoption of technical CP solutions, considering that those companies endemically suffer from a lack of financial resources for their survival. The proposed framework was validated through only four metal-mechanic manufacturers located in Brazil, and additional research considering a larger amount of companies belonging to other industries and located in other countries could strengthen the findings of this work.