Science and mathematics achievement gaps along racial, ethnic, linguistic, and socioeconomic lines have widened substantially over the past 20 years. Historically marginalized groups having significantly fewer "opportunities to learn" than their more advantaged peers. However, when students from non-mainstream backgrounds receive equitable learning opportunities, they are capable of attaining science outcomes comparable to their mainstream peers. The same is true for mathematics and, presumably, for other STEM subjects, as well. This STEM Smart Brief discusses the research and promising practices regarding providing high-quality curricula and instruction to all students, using classroom practices that support equity, connecting to students' cultural experiences and native languages, connecting to "real-world" problems, and organizing schools to foster equity. The strategies outlined in this brief offer promise to support the learning needs of all students while bolstering the learning of diverse learners in particular.