Graduate teaching assistants (GTAs) occupy a unique position in teaching and learning in higher education. Typically, individuals arrive at graduate school already socialized into disciplinary ways of knowing. GTA pedagogical professional development offers opportunities for GTAs to engage with current “best practices” and different pedagogical ways of knowing, and to initiate new and innovative practices. Research has demonstrated that as content knowledge and expertise develop, experienced instructors do not always recognize the ways that their expertise (e.g., how they organize materials or knowledge) can interfere with student learning (Ambrose, Bridges, DiPietro, Lovett, & Norman, 2010). GTAs are therefore well positioned to scaffold learning for content novices such as undergraduate students. The teaching preparation and pedagogical development of GTAs is not just a resource to support learning; in fact, the teaching and instructional skills that GTAs acquire can be transferred to professional domains outside academia (Osborne, Carpenter, Burnett, Rolheiser, & Korpan, 2014; Rose, 2012). GTA professional development has never been just training to fulfill a particular niche or to achieve a singular goal such as teaching; however, the current post-secondary climate of accountability and quality enhancement does bring the goals and purposes of GTA professional development into view.