In Europe, Content and Language Integrated Learning (CLIL) is becoming a popular and widespread practice of immersion education. In the Netherlands, for example, over 90 secondary schools offer a CLIL strand. Most CLIL teachers, however, are nonnative speakers of the target language, and do not have a professional background in language pedagogy. How, then, can these teachers effectively contribute to the target language development and proficiency of their students? In this paper we will discuss the findings of a study carried out in three secondary schools offering CLIL. The purpose of the study was to observe and analyse effective CLIL teaching performance facilitating language development and proficiency. The analysis was carried out by means of an observation tool for effective CLIL teaching, based on the following principles from second language pedagogy: (1) exposure to input; (2) content-oriented processing; (3) form-oriented processing; (4) (pushed) output; and (5) strategic language use. We will discuss how the CLIL pedagogy observed is related to content-based teaching and task-based language teaching, and provide recommendations for effective language pedagogy in CLIL. We will argue that not only CLIL teachers can profit from effective language-pedagogical approaches, but that language teachers can profit from effective CLIL approaches and experiences as well.