This research was conducted due to the limitation of independent instructional media for students that is based on the curriculum as a companion to mathematics textbooks. Where the textbooks do not connect mathematics with local culture, so that students are less familiar with their culture. This research aims to develop a valid, practical, and effective module for two-dimensional course based on ethnomathematics for fourth grade students of elementary school. The model employed in this development research was 4D model proposed by Thiagarajan that consisted of four stages: Define, Design, Develop, and Disseminate. The data analysis was done by using descriptive quantitative and qualitative. The results of this development showed that the module for two-dimensional course based ethnomathematics was valid and feasible; it was stated by the average score obtained from the experts (87.6%). Furthermore, the module developed obtained a positive response from the teacher and students; it obtained an average score of 88.5%. Then, the module was effective to improve student understanding, it obtained an average score of 81.55. Therefore, the module for two-dimensional course based on ethnomathematics is valid, practical, and effective to be used in the learning process.