Studies in science and mathematics education have shown that teachers' responsiveness to students' ideas, feelings, and experiences is critical for promoting epistemic agency, disciplinary engagement, and equity. Such responsiveness is particularly important for students whose cultures, backgrounds, and funds of knowledge have been traditionally marginalized in science, technology, engineering, and mathematics (STEM) classrooms. Yet, what allows teachers to enact responsive teaching is less clear. We argue that epistemic empathy--the capacity for tuning into and appreciating learners' intellectual and emotional experiences in constructing, communicating, and critiquing knowledge--is an essential driver of teacher responsiveness. In this work, we examine how epistemic empathy can serve to support teachers' attention and responsiveness to students' sensemaking experiences in the classroom and discuss emergent tensions that arise in this work. We end with implications for research and for teacher education to cultivate epistemic empathy as a resource for responsive teaching and a target for teacher learning.