<p>Visualization is a critical tool for reasoning and problem solving in science and mathematics classrooms. Its application has typically been framed as either internal, such as in the use of mental imagery, or external, as when we use diagrams to convey scientific ideas. In this study, we approach visualization from the perspective of embodied cognition to problematize this dichotomy in the context of professional learning with elementary school teachers. Through our interpretation of teachers’ collaborative sketching, we describe how their visualization practices were fundamentally influenced by their bodily interactions and the affordances of the material environment. Our study suggests that visualization needs to be understood as an embodied phenomenon and that professional learning with teachers should account for the bodily and material affordances of spatial visualization tasks.</p>