This contribution is about selected key issues related to the teaching of English to young learners (TEYL). Focusing particularly on primary school education, it reflects upon central theories and evidence-based research related to how young learners acquire and learn English. After an outline of central teaching principles, we develop the notion of a principled mindset. This provides the basis for a discussion of competence development and the integration of materials – focusing particularly on the role of authentic materials, scaffolding, classroom phrases, and the importance of literary texts. A basic introduction into how to plan competence-based lessons or lesson sequences follows. Throughout this contribution, examples aim to highlight the importance of a theoretical grounding for teaching practice.