Student-faculty partnerships position students as informants, participants, and change agents in collaboration with faculty members. Enacting one form of such collaboration, Bryn Mawr College's SaLT program pairs faculty members and undergraduate students in explorations of pedagogical practice. The program provides both context and case study for this form of Student-faculty partnership as a threshold concept in academic development. Like all threshold concepts, the notion of Student-faculty partnership is troublesome, transformative, irreversible, and integrative. This article draws on faculty reflections to explore what constitutes this threshold, the insights and practices that are possible if faculty cross it, and implications for academic developers.