This research was intended to develop mathematics learning tools on Statistics material on the seventh grade of junior high school through Science, Technology, Engineering, Mathematics based on Lesson Study for Learning Community and its effect on the students’ creative thinking ability. The method used was the mixed-methods combining qualitative and quantitative researches. Thiagarajan model as the developmental research was taken as the qualitative one. This research consisted of three classes; two experimental classes and one control class. The experimental design used was non-equivalent control group design. In normality test, the data obtained were normally distributed and the data were proved homogeneous based on the homogeneity test, so that it was necessary to do parametric data analysis by using One-Way ANOVA analysis. Based on the results of this research, the conclusions were summed up into: (1) The development of learning tools were categorized to valid, effective and practical, (2) The application of LSLC-based STEM had a significant effect on the students’ creative thinking ability which was indicated by a significance value of 0.000 (p<0,05).