Two-dimensional (2D) and three-dimensional (3D) shapes are crucial geometric concepts that children work with during their primary school years. Building an understanding of 2D and 3D shapes requires them to learn about the mathematical construct of dimension. Dimension is often described as length, breadth, and height for measurement purposes, and not necessarily as a geometric construct that allows children to see shapes as a plane or solid. This paper draws attention to how Year 5/6 children (9 to 11-year-old) use their language and gestures to communicate their understanding of dimension as they engage with physical and digital teaching and learning resources used during geometry lessons. Audiovisual data of six lessons was collected from a New Zealand primary classroom. The findings suggest physical teaching and learning resources such as play dough and sticks with adhesive may lead to quality differences in classroom interactions where some resources may allow opportunities for children to use their language and gestures to express their thinking about dimension and another set limit children’s responses to one or two words.