The purpose of this article is to introduce the theory of interfaith learning and development to the scholarly community. Building on the work of others, the authors adopted an interdisciplinary, equity-oriented approach to developing the theory, which also serves as the basis for a framework intended to guide and inform interfaith practice. Development occurs through exposure to and participation in college experiences that help students achieve outcomes related to religious, spiritual, and worldview development. Outcomes specific to interfaith learning and development include pluralism, self-authored worldview commitment, appreciative knowledge of religious and non-religious traditions, and appreciative attitudes toward religious and non-religious narratives.As the public continues to scrutinize higher education for its societal value, student development theorists-and by extension their theories-must sustain their distinctive relevance, not only as both academic and pragmatic, but as responsible and timely. Indeed, "bridging theory and practice" continues as the mantra of the student development field, with foundational texts, curricula, and practices pivoting on the fundamental notion that knowledge of student and context loses meaning without pragmatic application to-if not deference toward-deeper understandings of students-in-context. Theory with practice genuflects to theory in practice.What does it mean for theory in practice to be responsible and timely? Responsible student development theory-building must account for the experiences of students with different identities and narratives and the practices that help them make developmental gains. Critical questions must continue to disrupt exclusive, hegemonic, and irresponsible theory building: Who benefits from this practice? How have institutions succeeded or failed to design inclusive practices that invite, welcome, and appropriately challenge and support all students? aMatthew J. Mayhew