Teaching is a primary responsibility of many academic librarians. However, despite the job duties, many academic librarians do not see themselves as teachers. To determine how participation in the Scholarship of Teaching and Learning (SoTL) impacted academic instruction librarians' teacher identity the authors conducted an explanatory sequential mixed methods study. Using the theoretical framework, Communities of Practice, results from the quantitative survey demonstrated participation in SoTL did impact academic librarians' teacher identity. The qualitative interviews explained the quantitative data. Study findings have implications for academic developers, Library and Information Science graduate programs, and academic library administrations.