This article sets out to determine the knowledge base of teaching in linguistically diverse secondary schools in England. Based on extensive interviews with the teachers across two schools, the article distinguishes a set of good practices focused on flexibility and differentiation. These cover diversifying teaching resources by employing bilingual materials and dialogic tasks, as well as making adjustments to teaching by simplifying input and covering cultural references. These practices are featured by ‘a situated child-centred approach’ which is underpinned by 10 core principles of multilingual classroom pedagogy for English as an additional language. Implications for education policy and practice are also debated.