Teacher learning, as well as the development and testing of curriculum materials, are key for teaching lessons that bring the goals of the Next Generation Science Standards to life in classrooms. Lesson study is a process that links standards, teacher learning, curriculum materials, and instructional enactment together to facilitate student learning. This article has two goals: (1) describe the essential features of lesson study and, (2) discuss the challenges in facilitating and researching both teachers' and students' learning through this process. Lesson study's adoption is relatively new in the United States, thus it is important to develop shared understanding of its features and how to study its impact.