<p>Prior research proposed a model of teacher noticing comprised of attending, interpreting and shaping. To date, little research has elucidated what the third component, shaping, looks like in practice. This study addresses this gap by examining teacher noticing as it occurs during instruction. Qualitative analysis of interviews with nine middle and high school mathematics teachers reveals three types of shaping practices teachers report they enact to advance their in-the-moment noticing. These shaping practices relate to different aspects of the instructional system and include eliciting details, leveraging participant structures, and creating and using material and social resources. We describe each practice and elaborate several distinctions in how the practices occur during instruction. In doing so, we show how shaping supports teachers’ noticing of student mathematical thinking and advance research on teacher noticing as an interactive, situated activity.</p>