This research aims to knew the differences critical thinking skills between Senior High School 1 Tuban (adiwiyata school) and those in Senior High School 4 Tuban (non adiwiyata school). The method used in this research included descriptive study of comparative using quantitative and analyzed using descriptive statistic. The result of critical thinking skills were obtained through tests on a biological material environment or climate changes and recycling waste. Students have critical thinking skill if their test score obtained ≥75. The subject of this research were 30 science students grade X-6 of Senior High School 1 Tuban and 34 science students 34 science students grade X-1 of Senior High School 4 Tuban. Analysis results of this research obtained critical thinking skills of students of SMAN 1 Tuban were 40% which included less category and students of SMAN 4 Tuban were 17.5% which included very less category. The result of the research was the critical thinking skills students of Senior High School 1 Tuban are better than students of Senior High School 4 Tuban. Keywords: critical thinking skills, adiwiyata, non-adiwiyata.