The National Research Council's 2012 "Framework for K-12 Science Education" states that science education should "provide all students with the background to systematically investigate issues related to their personal and community practices … frame scientific questions pertinent to their interests, conduct investigations and seek out relevant scientific arguments and data, review and apply those arguments to the situation at hand, and communicate their scientific understanding and arguments to others" (p. 278). It also states, "Arguably, the most pressing challenge facing U.S. education is to provide all students with a fair opportunity to learn" (p. 281). The continued growth of the multilingual learner K-12 population presents challenges for science teachers. A 2018 National Academies of Sciences, Engineering, and Medicine report emphasizes the cost of the persistent multilingual learner opportunity gap in science, technology, engineering, and mathematics, and it identifies exclusionary practices barring multilingual learners from equitable inclusion in rigorous science education. The report recommends changes in policy and practice to overturn this disparity by leveraging the strong connections between sense-making in science and the language-in-use approach to English language development. In response, WIDA and the National Science Teaching Association formed Making Science Multilingual to support equitable and inclusive forms of science instruction through which all students, but especially multilingual learners, can learn science and language simultaneously. To guide this work, the Making Science Multilingual team devised eight design principles to define the integration of contemporary three-dimensional science and language-in-use pedagogies. These principles will guide educator resource development at both organizations and facilitate critical examination of how well educator resources support inclusion of multilingual learners in rigorous science learning. [Support from the National Science Teaching Association and WIDA.]