This study aim to explore the effects of presenting anomalous data on improving student’s critical thinking ability. This study is an experimental research conducting on one-group pretest-posttest design. Purposive sampling was used in this study, where one class group was used as a sample of the study, namely 36 students of senior high school at MA Hidayaturrahmah NW Menggala, North Lombok, West Nusa Tenggara, Indonesia. The data of CT ability collected by instrument refer to Ennis-Weir Critical Thinking Essay Test. The data analysis descriptively and statistically were done to process the data of research. Path analysis was used to evaluate the contribution of presenting anomalous data on improving student’s critical thinking ability. The results of this study indicate that the presenting anomalous data at initial learning have an effect and contribute on improving student’s critical thinking ability. Further reviews are described in this article.