Coteaching offers a model for the school-placement element of pre-service science teacher education, based on its demonstrated positive impacts on lessening classroom anxiety, supporting inquiry-based science teaching, improving students' attitudes, and addressing diversity effectively in science classrooms. Coteaching between pre-service and in-service teachers is used to lessen the gap between theory and practice, to develop reflective practice and to develop pedagogical content knowledge. Explanatory frameworks have been proposed for coteaching, and we suggest that Vygotsky's zone of proximal development helps to propose a more nuanced developmental and learning explanatory framework which provides pedagogical structures for implementation and highlights the importance of the social environment for learning. In providing structure and tools for effective implementation of coteaching, our model addresses three core elements of coteaching: coplanning, copractice, and coevaluation. The model was piloted in relation to pre-service teachers' development in reflective practice and reducing the gap between theory and classroom practice.