The concept of community in higher education is broadly defined yet often exclusively linked with the undergraduate student population. Based on a two-year qualitative study at Oregon State University and the Massachusetts Institute of Technology, this article explores the notion of doctoral student community. Community as experienced by science doctoral students is unique and complex and is influenced by multiple communities including the discipline, institution, department, lab and advisor. Each community may be more salient at different junctures of the doctoral journey. A model depicting these nested communities was developed and is discussed along with implications for practice. (Contains 1 figure.)