This contribution tackles the notion of metacognition. This notion is considered as central to learning outcomes for it involves the awareness and regulation of thinking processes by learners themselves. This notion seems to be important since, after a peak of publications during the years 1998-2000, it is currently addressed by numerous articles about science teaching and learning at elementary and secondary educational levels (cf. ERIC database). The first part of this contribution discusses the state of the art about metacognition within science education and elsewhere in order to elicit relevant indicators which could underpin further research. The second part discusses the validity of tools (i.e. specific activities and questionnaires) aiming to identify and assess pupils’ metacognition in relation to science teaching and inquiry, and teacher commitment in relation to collaborative activities and the introduction of innovative methods.