SETS (Science, Environment, Technology and Society) approach for learning is important to developed in middle school. It can enhance students critical thinking ability. This research aimed to determine feasibility and effectivity of Natural Science Modul with SETS approach to increase student critical thinking ability. This is Research and Development type design. The module developement was done by invitation, exploration, explanation, concept fortifying, and assessment. Data collection was done used questionnaire and questions test. Tests are performed used pretest posttest with control group design, involves two classes as samples that was choosen randomly consist of 32 students in each group. Descriptive data analysis was used to analyze the module feasibility and t-test was used to analyze the critical thinking ability. The results showed that the feasibility of the module development have a very good results based on assessment of the experts, practitioners and their wives. Based on the t-test results, there are significant difference between control class and experiment class (0,004), n-benefits of control and experiment class respectively 0,270 (low) and 0,470 (medium). It shows that the module is more effective than the textbook. It is able to improve students critical thinking ability and worthy to used in learning.