As academic librarians' instructional responsibilities evolve, it is useful to consider what factors influence how they consider their teacher identities. In this research, the author used a survey instrument grounded in transformative learning theory to explore whether librarians with varying years of experience in instruction held different beliefs about how their teaching identities had developed. She found that individuals' years of teaching experience impacted whether fellow librarians or those outside of librarianship influenced how they thought of themselves as educators. Moreover, academic librarians who had more experience indicated that changes in their job responsibilities impacted their instructional identities at greater rates than their less experienced counterparts. Understanding these influences can help library leaders to design, provide, and facilitate meaningful learning opportunities for instruction librarians.