This paper primarily investigates the interactional unfolding and management of "claims of insufficient knowledge" (Beach and Metzger 1997) in two English language classrooms from a multi-modal, conversation-analytic perspective. The analyses draw on a close, micro-analytic account of sequential organisation of talk as well as on various multi-semiotic resources the participants enact including gaze, gestures, body movements and orientations to classroom artefacts. The research utilises transcriptions of 16 (classroom) hours of video recordings, which were collected over a six-week period in 2010 in a public school in Luxembourg. The findings show that establishing recipiency through mutual gaze and turn allocation practices have interactional and pedagogical consequences that may lead to claims of insufficient knowledge. Furthermore, the findings illustrate various multi-modal resources the students use (e.g. gaze movements, facial gestures and headshakes) to initiate embodied claims of no knowledge and to show specific exchange structures. Finally, we suggest that certain interactional resources, including embodied vocabulary explanations and Designedly Incomplete Utterances (Koshik 2002), deployed by the teacher after a student's claim of insufficient knowledge may lead to student engagement, which is a desirable pedagogical goal. Our findings have implications for the analysis of insufficient knowledge, for teaching, teacher education and in particular for L2 Classroom Interactional Competence (Walsh 2006).