International Teaching Assistants (ITAs) need to be able to communicate their ideas, show competence, and construct academic identities in order to be successful college instructors. Using one strand of identity theory focusing on the relationship between social structures and identities (Stryker & Burke, 2000), I examined identity roles represented in ITAs' self-mentions during teaching demonstrations. I followed Zareva (2013) in studying ITAs' use of first person pronouns I, me, and mine and the determiner my to project professional identities. In order to account for the wide range of identity roles represented in ITAs' teaching, I used two additional frameworks for academic and institutional identities (Tang & John, 1999; Farrell, 2011). Data was taken from a corpus of ITA teaching demonstrations as part of an oral English test in which each ITA had given a 5-minute mini-lecture on a topic relevant to their field (N=149). Analysis of data revealed that the academic genre identities comprised the largest proportion of all identity types (52.9%). In these instances, ITAs demonstrated authorial power through outlining the topic, representing or guiding others, and holding opinions. Professional identity roles (26.8%) were projected when ITAs provided knowledge, spoke with authority, or initiated interactions. The third most common identity roles (15.7%) were those exclusive to the spoken register that did not necessarily relate to the content of teaching demonstrations. Finally, institutional identity roles (4.6%) were seen when ITAs referred to their personal experiences or membership in a community of practice. Even though the academic genre identities were the most prevalent, teaching demonstrations included identity roles with relatively lower authorial power. The lower proportion of professional and institutional identity roles can be explained by the fact that as newcomers in academia, ITAs are in the early stages of constructing, reconstructing, and negotiating their identities as teacher members in the US higher education community.