This study investigates the knowledge that experienced teachers draw on when fostering students' reflections. Reflective skills are crucial for advancing students' learning. In order to promote students' reflection productively, extensive support and scaffolding from teachers is indispensible. However, teachers are in need of more guidance in this area. To inspire pedagogies for teacher training, this study provides insight into the knowledge that teachers employ when they are engaged with promoting their students to reflect. Video vignette interviews were administered to 36 teachers in secondary vocational education for nursing to elicit their knowledge. Interview transcripts were coded using categories for assessing teachers' curricular, pedagogical and instructional knowledge. To investigate relations between the elements of teachers' knowledge, we performed a lag-sequential analysis that enables statistical testing of observed sequences of categorised events. Four salient relations between elements of teacher knowledge emerged: (1) instructional knowledge as instrumental to construing pedagogical knowledge; (2) instructional knowledge contingent on pedagogical knowledge; (3) instructional knowledge and curricular knowledge related to fostering critical reflection; and (4) instructional knowledge and curricular knowledge related to fostering planning. Implications for teacher training are discussed.