This study explores graduate engineering identity and the influence of peer and academic advisor relationships using an intersectional lens. A survey collected 1,754 U.S. engineering graduate students’ reports of their experiences, identities, and motivation and explored two research questions using a combination of MANOVAs and moderated regressions. Peer and academic advisor attitudes are positively related to all aspects of graduate engineering identity. Students’ identities significantly predicted mean differences across scientist, engineer, and researcher identities and their sub-constructs. Male and female Asian students scored lower than their peers in self-assessments of their scientist recognition and performance/competence, while other groups showed more variability. Advisor relationship scores were similar for all students, but peer relationship scores were lower for Students of Color. Students’ social identities also led to differences in the relationships between advisor/peer relationship scores and engineering identity. Men and Women of Color often reported significantly different effects of peer relationships on identity, with men reporting positive effect and women reporting no effect. Asian women and Underrepresented Women of Color differed from White women, where Women of Color reported stronger benefits from positive academic advisor relationships. This paper explores these results and the implications for researchers and educators working with graduate populations.