Positive teacher-student relationships are important for student learning. One factor that promotes such relationship is closeness. Yet, the teacher-student relationship is a professional one and there are limits to how close teachers and students can get without crossing this professional boundary. The purpose of this paper is to use spatial theories in order to explore how teachers and students in secondary education view and navigate border territories of positive and professional teacher-student relationships. Data is drawn from a combined case study where teachers and students were interviewed. Spatial theory aids the analysis, where we ask: Where, when and how are positive teacher-student relationships negotiated in schools, how do teachers and students reason regarding the borderlands of teacher-student relationships, and how do they navigate them? Preliminary results include instances when teachers intentionally work at attaining closeness, and when they back off to distance themselves in order to keep a professional distance. Students, although they appreciate closeness, are very sensitive to teachers trying to overstep the boundary. Both teachers and students point to informal situations and places in schools as significant for building positive relationships. The scientific significance includes the novel use of spatial theory that is fruitful for shedding new light on interpersonal processes in schools, and the results are of value for teachers as well as for future research on understanding and improving professional teacher-student relationships.