Teachers' questions shape the instructional environment and the direction of mathematics discussions in critical ways. This article is the product of a research study on the relationship between teachers' questions and student engagement in the Standards for Mathematical Practice (SMP) during whole-class discussions. Using classroom video gathered during the first year of a study of teacher professional development, the authors identified instances of student engagement in the SMP. They then analyzed the types of questions teachers asked students in discourse sequences that resulted in this engagement, as well as in sequences that did not. The authors looked for patterns in the types of questions asked and closely examined interactions between teachers and students to better understand how certain types of questions created or limited opportunities for student engagement in the SMP. They present and illustrate key findings about teacher questioning from our study and discuss the implications of these findings for classroom practice.