One of the most researched domains of computing education research (CER) that attracts attention is computing education in schools, starting from pre-primary level up to upper secondary level (K-12). A high number of initiatives and related research contributions have appeared over half a century of computing history in schools. This chapter presents an overview of CER in the K-12 domain, including globally influential movements such as that of Logo pedagogy, constructionism, inquiry based learning or computational thinking (CT). Development of CT in education, based on a number of previous reviews on CT and K-12, paints a diverse picture of the approaches, educational technologies, pedagogical innovations, and related challenges such as lack of teacher training or shortage of learning resources. This article presents also a scientometric overview of CER research in the K-12 domain. The analysis identifies the top topics of research, and foundational articles. While much of the research is centered around the US, key research from other parts of the globe is also highlighted. Emergence of new trends such as teaching artificial intelligence and machine learning in schools are also discussed.