Within the broader landscape of the European Higher Education Area, teacher education receives increasing significance as an academic field that contributes to the quality of the teaching labour force and consequently impacts student learning. This paper aims to explore the European Teacher Education Area (ETEA) by analysing to what extent and how mechanisms, processes, and key agents of Europeanisation, internal or external to the European Union (EU), influence the transformation of teacher education policies and practices in Europe. Transformation is understood in the context of Europeanisation, and emphasis of the analysis is placed on the process rather than the content of transforming teacher education in Europe. To this end, data have been collected through document review and expert interviews with European policy officials. As a result of qualitative content analysis, the data have been clustered and analysed according to the following categories, which mutually reinforce each other: (1) policy coordination; (2) cross-sectoral instruments; (3) evidence-based management; (4) the Bologna process; (5) educational programmes; and (6) stakeholder pressure. Findings provide a conceptual framework for mapping the ETEA as a complex policy ecosystem that includes vertical and horizontal procedures of Europeanisation. The EU has developed extensive capacities to influence teacher education in Europe and increasingly involves other sectors, such as employment, in this process.