Questions asked by teachers are vital to maintaining and sustaining learner engagement. In Hong Kong secondary classrooms where English is used as the medium of instruction (EMI), productive teacher questioning is key to promoting both language and content learning. Drawing on classroom observations and in-depth interviews, this study investigated the questioning practices of two teachers from EMI schools in Hong Kong. Quantitative and qualitative analyses of the data revealed that the teachers adopted different approaches to questioning. Their questioning practices can be captured by a dynamic model of two intersecting dimensions: cognitive demand (lower- and higher-order questions) and interactional orientation (authoritative and dialogic discourses). The findings of this study support the notion of teacher questioning as pedagogy and demonstrate how productive teacher questioning can mediate learner engagement. A guiding framework is proposed for productive teacher questioning that relies on the synergistic combination of cognitive demand and interactional orientation.