The focus of this study is on interactions among teachers, and other participants, in the collaborative design of mathematics teaching and learning artefacts. There is a variety of modalities of collaborative design of these artefacts around the world, and research has shown the benefit of this activity for students\u27 learning and teachers\u27 professional growth. My purpose in conducting this study was to understand what happens inside these teams of collaborative design in terms of participants\u27 interactions and activities. I decided to take a social approach in researching these interactions. This research was conducted in three stages differing in the types of data sources and data generation. The first stage consisted of the study of a single case in which I participated as a member in a team of collaborative design. I analysed the conversations and actions held during the design process identifying two emerging themes: (1) the focus of the conversations and actions, and (2) the roles held by the participants of collaborative design. I characterized interactions using these two themes, which I consider as dimensions of interactions in teachers\u27 collaborative design. In the second stage of this study I looked at other cases of collaborative design. Participants from three different modalities were contacted in order to identify resonances and dissonances with the case analysed in the first stage. Lastly, in the third stage, three pieces of literature served as second-hand data to explore large-scale modalities of teachers\u27 collaborative design. Considering all the cases included in the second and third stages, I refined and extended the characterization for interactions among participants in teachers\u27 collaborative design. The resulting characterization for interactions serves as a language that acknowledges the diversity of both the settings in which collaborative design can be conducted and the participants\u27 roles played in each case. Such characterization has implications for both practitioners and researchers in mathematics education interested in teachers\u27 collaborative design and professional development
