As former and current STEM (science, technology, engineering, and mathematics) school teachers in Singapore, we explore the challenges we both experienced while teaching at different STEM schools. Through this article, we make a case for the teacher preparation programs locally and around the world to give more attention to a changing education landscape with emerging specialized STEM schools. Nonetheless, even though specialized STEM teacher preparation is needed, we also caution that having such a specialized program may limit teachers' horizontal transition to mainstream schools and awareness of the contextualized needs of more diverse learners.