Relative to their middle and high school teacher counterparts, elementary science teachers are both uniquely situated and uniquely challenged for excellent science instruction. More than 90 percent of elementary teachers work in self-contained classrooms, meaning they have opportunities to connect their science instruction with English language arts, mathematics, and social studies. However, teachers in self-contained settings also face formidable obstacles. Accountability pressures in English language arts and mathematics draw instructional time away from science. Further, because teachers in self-contained classrooms are responsible for all core subjects, their preparation tends to be very broad in terms of disciplinary focus. This brief discusses results from the 2108 NSSME+, a recent major national survey of K-12 schools and teachers in the US. It describes differences in elementary science instruction when it occurs in self-contained vs. non-self-contained classrooms in grades 3-5. It also describes differences in teachers of these classes. [For "Report of the 2018 NSSME+," see ED598121.]