The study is done to identify the critical thinking skills of students in senior high school. This study is aimed to describe the critical thinking skills students covering five skills, standard clarification, standard endorsement, conclution (inference), advanced clarification, and strategies and tactics. The research was conducted in SMA Muhammadiyah 1 Banjarmasin. The subject research was tenth grade students at SMA 1 Banjarmasin in the academic year 2015/2016. The researcher took 30 students as the sample.The research is descriptive quantitative research by giving test critical thinking skills to students of multiple choice. The result Showed critical thinking skills that students at elementary clarification by 95.83%, basic suport by 56.67%, 76.67% by inference, advanced clarification 3:33%, and strategies and tactics of 95.83%. The result showes that students have a good score on standard clarification, clonclusion (inference) and strategies and tactics, but still low on standard clarification and advanced clarification.