Different goals of high schools and vocational schools in Indonesia become the main factor causing the distinction of preparedness of chemistry teachers in using the Science, Technology, Engineering, and Mathematics (STEM) approach in their teaching. Yet the High School Chemistry Teachers (HSCT) and Vocational School Chemistry Teachers (VSCT) need to have positive perceptions about STEM since it offers students meaningful chemistry learning. Through an explorative survey method, this research investigated in-service chemistry teachers' perspectives toward the potential of STEM learning in high school and vocational schools of chemistry. A number of 131 in-service chemistry teachers (82 HSCT and 49 VSCT) from Yogyakarta, Indonesia was voluntarily participated in this research through a saturated sampling technique. Perception Scale on STEM (PC-STEM) consisting of 54 closed-ended questions and seven open-ended questions were used to collect the data. Data analysis techniques involved one-way MANOVA testing, descriptive statistics, and content analysis with interpretive coding. The findings showed that HSCTs' and VSCTs' perspectives toward STEM were in the good category. Thus, integrated STEM learning is potential to be used in chemistry lessons at high school and vocational school. However, there were not any statistically significant differences between HSCT and VSCT participants' perceptions of how STEM was being used to teach chemistry. Unfortunately, despite their perception being good, both groups of teachers signified a poor experience in applying STEM in their chemistry lessons. Therefore, teachers' professional development program about STEM is needed for chemistry teachers to successfully implement STEM-based chemistry learning.