A growing number of studies have explored the ways how teachers contingently respond to students' unexpected responses or a lack of student responses in second language classrooms. From a sociocultural perspective, teacher contingency involves a departure from the lesson plan in local response to the unexpected or unforeseeable actions in the classroom interactions (van Lier, 2001). This study adopts translanguaging as an analytical perspective in order to examine how a teacher employs various resources to contingently respond to students' initiatives and reformulate his utterances in order to prompt student participation. The data are based on a larger linguistic ethnographic project in a Hong Kong English-Medium-Instruction secondary history classroom. This paper reconceptualizes the notion of teacher contingency and argues that the process of how the teacher contingently responds to the unexpected outcomes that arise in real-time interactions is a process of translanguaging. Such a process requires the teacher in orchestrating the available linguistic and multimodal resources to construct pedagogical actions on the spot, instead of being planned in advance.