Policymakers and the public are increasingly asking educators to approach instruction from a STEM perspective, integrating science, technology, engineering, and mathematics to prepare students for future careers. At the same time, administrators are directing teachers to make learning more communal and student-driven, emulating the workforce students will likely enter. Often there is no specific training or support for the teachers who lead these STEM-oriented, collaborative classrooms. A 2013 report issued by the Chicago STEM Education Consortium noted that one fundamental challenge is the absence of a clear and common definition of STEM education (C-STEMEC, 2013). This article defines the the goal of the authors as building a cohort of K-8 teachers who can engage their students as mathematical and scientific thinkers. Two questions drove their work: (1) How to get teachers to collaborate around STEM education in a meaningful way; and (2) How to create a common understanding of what science and math integration looks like in the classroom? An Illinois State Board of Education Math and Science Partnership Program grant allowed the authors to explore these questions through a Practices in Mathematics and Science: Connections and Collaboration project.