This qualitative study examines communicative processes associated with graduate students (N = 124) in their struggles with the impostor phenomenon (IP, commonly known as impostor syndrome) and their integration into and experience in graduate programs (aspects of organizational assimilation). We identified two mutually implicative relationships. First, participants described the interplay of their attempts to assimilate into the graduate program and management of IP (internal factors). Second, participants narrated departmental, communicative efforts by others (peers, faculty advisors) and the department culture that communicated expectations (external factor) as strongly interlinked to graduate students' IP management and their organizational assimilation. We offer findings focused on the intersection of communication and instruction, and extend theorizing with an integrated model depicting narrated individual-departmental processes that may shape IP management and organizational assimilation. We conclude with a discussion about theoretical implications and practical applications for training faculty to improve their guidance and mentoring of graduate students to reduce IP.