The DMAIC (Define, Measure, Analyze, Improve, and Control) method is the main method of the Lean Six Sigma methodology, focused on solving problems where the root cause is unknown. Although DMAIC has a well-defined structure, many professionals — especially those who are new to Lean Six Sigma — face difficulties in selecting the appropriate tools for each stage, due to the number of options available. This research aimed to develop the "Belt Flow Framework", a decision support model developed especially to guide professionals in selecting the appropriate tools for each stage of the DMAIC method, according to the characteristics of each process improvement project. The methodology chosen was the construction of theory from multiple cases, proposed by Eisenhardt (1989), where six Lean Six Sigma professionals contributed through a structured questionnaire, allowing intra-case and inter-case analyses. As a result, a framework was developed, which was initially developed in a flowchart format and later implemented in a digital and interactive application, allowing users to logically navigate and identify which tools to apply at each stage of DMAIC. The results demonstrated high acceptance by participants, who classified the Framework as clear, applicable and useful in reducing uncertainty in tool selection. This study offers a theoretical and practical contribution to the Lean Six Sigma field, offering a structured, validated and accessible solution to a common challenge in the execution of DMAIC projects.