The level of mastery of mathematics is evidence to evaluate the excellence of the school mathematics curriculum. However, the effectiveness of the delivery of mathematical learning remains an issue when the level of mastery is still low. Therefore, curriculum transformation is required to ensure that mathematical mastery is at a satisfying level. Various suggestions and interventions have been undertaken to enhance the mastery of students' mathematical concepts and achievements, including through the construction of teaching modules. Therefore, the objective of this study is to develop the Meta-Seller Tutoring Module (M-ST) and subsequently determine the validity and reliability of the module. This M-ST module is developed through a design and development research that takes the ADDIE Model as an instructional design guide. This M-ST module incorporates peer tutoring and metacognitive learning strategy models as it is content and module activities to help the improvement in students' mastery of mathematics. A total of 10 experts, a mathematics teacher, and 31 students participated in the study to determine the content validity and reliability of the module. The results of the analysis of the content validity of the module found that it is in an excellent rank with a validity index of 0.86. While the value of the reliability coefficient is 0.953 which also indicates that this module is at a very high level of trust. Based on the results, it can be concluded that this module is very useful and can be used as an intervention in mathematics learning. Teachers can integrate this module into teaching and learning to produce effective mathematics learning. By using this module, teachers can provide students with learning aids through interactive materials to create active learning.