Assessing students' prior knowledge is essential for effective teaching. Understanding what students already know—and don’t know—enables faculty to address misconceptions, fill knowledge gaps, and build on existing understanding. In this workshop, we’ll explore strategies for assessing prior knowledge and using it to achieve teaching and learning goals. Participants will also develop a plan to prioritize this practice in their classes, building skills to align instruction with students' strengths and needs, while embracing variation in their levels of understanding.