Determining and maintaining interpersonal boundaries with students is an ever-present yet rarely-discussed element of teaching graduate students. Where to meet students for advising appointments, how much to self-disclose in the classroom, and whether to collaborate with students on community projects--these are typical of the challenges that graduate school faculty encounter regularly as classroom teachers, and program, thesis, and practicum advisors. This article is based on a grounded theory study of relational practice between master's students and professors; while the study was not designed to explore interpersonal boundaries per se, participants discussed power, position, and boundaries, thus providing significant data to explore this topic. With positive relationship scholarship and relational cultural theory as sensitizing concepts, this study included in-depth interviews of 10 matched pairs of master's alumni and professors wherein each member of the dyad considered the relationship to be meaningful. Grounded theory dimensional analysis methods were used to analyze the data and identified categories including the following: professors' awareness of positionality, professors establishing boundaries, students' awareness of positionality, and students and professors working close to the boundaries. These categories were used to examine extant literature and propose an expanded understanding of interpersonal boundaries between students and teachers.