Critical thinking ability to develop students' mindset in creating 21st century critical thinkers. An alternative to this ability training is to get used to completing Higher Order Thinking Skills (HOTS) based on learning as an embodiment of higher thinking. The critical thinking criteria used are Focus, Reason, Inference, Situation, Clarity, and Overview which are acronymized as FRISCO. This study aims to analyze students' critical thinking skills about HOTS in terms of FRISCO criteria. The method used in this research is descriptive quantitative. Data was collected by presenting 6 items of question, unstructured interviews, and documentation. By using purposive sampling technique, the distribution of the HOTS test instrument was given to 63 students in class XI IPA 3 and XI IPA 5. Interviews were conducted to students with high, medium, and low abilities for deeper analysis. The results showed that the category of mathematical critical thinking skills of students in class XI IPA 3 and XI IPA 5 was at a medium level with an average score of 38.20. If viewed from the FRISCO criteria, the scores and categories in solving HOTS questions each criterion is Focus of 3.21 is classified as high level, Reason of 2.54 is classified as medium level, Inference of 1.68 is classified as medium level, Situation of 2.11 is classified as medium level, Clarity 0.94 is classified as low level, and Overview of 0.98 is classified as low level.

Keywords: Mathematical critical thinking, Higher Order Thinking Skills (HOTS), FRISCO