In this article, we describe the experiences of two preservice teachers (PSTs) who served as teaching assistants (TAs) in a secondary mathematics teaching methods course. As TAs, the PSTs approximated practice by being independently responsible for a learning environment and leading discussions with groups of students. Although the PSTs felt stress and pressure in their new role, findings suggest that this experience, coupled with opportunities for reflection, contributed to their growth. Given both these findings and the impetus to increase opportunities for authentic learning, we encourage teacher educators to think more broadly about ways of contributing to PSTs' learning.