Background: Tasks that involve retrieving information from memory, such as answering short answer questions, are more effective at improving learning than restudying, concept mapping, and other study techniques. However, little is known about how often teachers naturally provide these retrieval practice opportunities during lectures and classroom discussions. Aims: To identify how often teachers ask questions that require retrieval, what types of retrieval questions they ask, and whether teachers in high-growth classrooms differ in their use of retrieval questions compared to teachers in low-growth classrooms. Sample: The sample included twenty middle school mathematics classrooms that showed high growth on a test of mathematics achievement and twenty with low growth. For each classroom, we examined a videotape of one class period. Methods: We coded the number of teacher questions in each lesson, and the number and type of questions that provided an opportunity for retrieval. Results: We found wide variability in the frequency and type of questions asked across classrooms. On average, almost half of the non-classroom management questions provided an opportunity for retrieval. However, teachers in high- and low-growth classrooms asked similar numbers and types of retrieval questions. Conclusions: Teachers naturally use a wide variety of retrieval questions in their mathematics classrooms. As such, improving their use of retrieval opportunities will require only small changes to their natural practice, rather than large changes to their instructional style.