The low level of students’ higher order thinking skills (HOTS) has been the main problem of education in Indonesia. This study aimed to determine the difference of students’ HOTS taught by using POE and Guided Discovery learning models. This quasi-experimental research involved 34 students of X IPA 3 and 32 students of X IPA 4 at SSHS 1 of Sungai Ambawang as the sample. The data obtained by using test which was analyzed using Mann-Whitney U-test. The results showed that the students’ HOTS who were treated with POE were significantly higher than those who were taught using Guided Discovery learning. Therefore, it is suggested to implement POE to improve students’ HOTS.