Ambitious federal goals for preparing students for careers in science, technology, engineering, and mathematics (STEM) fields require coordinated efforts and supports for the country's science instructors. Increased attention to the needs of science instructors and the provision of supports to address those needs are particularly important in light of documented shortages of STEM kindergarten through 12th grade (K-12) teachers across several states. In this Data Note, researchers use nationally representative survey data of K-12 teachers from the 2020 American Instructional Resources Survey to examine how teachers' science instruction is supported and whether these supports differ from those that teachers report for English language arts (ELA) and math instruction. Researchers found marked differences in teachers' reports of instructional supports as they relate to the science instructional environment relative to teachers' reports on instructional environments in ELA and math. These differences suggest that access to formal materials, feedback, and support is lacking for science instruction relative to instruction in ELA and math.