Mixed-methods (MM) designs have gained increasing interest in educational research. Still, many studies collect quantitative and qualitative data but report these data separately and do not attempt to integrate them in practice. The aim of this article is to discuss the purposes and processes of integrating qualitative and quantitative data in an MM classroom interaction study. Issues regarding mixing and integration, including how to overcome integration barriers, are discussed. Based on this outline, the study then presents details about the various integration processes adopted in a recent MM study on classroom interaction in Norway. The possibilities and challenges of integration to produce new knowledge and a deeper understanding throughout the research process in classroom studies are illustrated with a specific focus on points of interface. A key issue is whether the new knowledge obtained in an MM study is more than the sum of the individual quantitative and qualitative parts. Using selected questions from the MM alphabet proved a helpful heuristic for guiding the iterative processes of integration and provided richer explanations and an enhanced understanding of the implementation and impact of a complex classroom intervention initiative. The study provides a new methodological contribution to the MM literature by examining the integration processes and challenges faced in a specific study.