Mathematical curiosity is an important aspect that students have, especially in learning mathematics. However, in today′s technological era, students in Indonesia feel that mathematics is a scary learning due to students’ lack of understanding so that students feel uninterested in mathematics. Furthermore, a STEM learning that emphasizes the relationship between science, technology, engineering, and mathematics emerged as a learning innovation that is quite popular with students. With the use of technology in STEM learning, it is proven that more and more students are interested in this learning. The purpose of this study was to analyze the achievement of students’ mathematical curiosity after applying technology in STEM learning. Data were collected using questionnaire method based on mathematical curiosity indicators. The research subjects were 90 students in Indonesia who applied technology in STEM learning. After distributing questionnaires regarding mathematical curiosity to research subjects, data processing was carried out by analyzing the level of achievement of respondents. The results showed that most of the subjects who have applied technology in STEM learning have been able to show good mathematical curiosity based on all indicators of mathematical curiosity. The average index of respondents’ achievement level obtained from all subjects is 69%, which means that the average subject is at a good level of mathematical curiosity. With the achievement of good student mathematical curiosity, STEM learning, which includes the application of technology, is feasible to be implemented in schools.