There have been strong calls to action in recent years to promote both school choice and the learning of science, technology, engineering, and mathematics (STEM). This has led to the burgeoning development of STEM-focused schools. Nine STEM-focused charter and 2 STEM-focused magnet schools that serve elementary-aged students were examined to assess the achievement of students who transfer to these schools, as compared to students transferring to non-STEM schools, in the content areas of mathematics, language arts, and reading. The achievement of students transferring to STEM-focused elementary schools was also evaluated after 3 years at their new school and compared both to students’ own prior achievement at their old school and to achievement of students comprising comparison groups. Results generally indicated no effect of STEM-focused magnet schools, but did indicate some positive effects of STEM-focused charter schools.