Undergraduate teaching assistant (UTA) programs pair students with faculty to enhance teaching and learning in the classroom. These programs have the potential to offer a high-impact experience (Kuh, 2008); students feel more connected to learning when meaningfully engaged. UTAs develop important relationships with faculty mentors, hone problem-solving skills, feel more connected to the institution, and may begin to see themselves as future faculty. When the authors' institution celebrated the 25th anniversary of its UTA program, they thought it a good time to reflect and assess. This article delineates principles of best practices for institutions seeking to begin or revise a UTA program.