Peer educators can be a powerful addition to classroom learning environments. Traditionally, the university science teaching model relies on graduate teaching assistants (GTAs) to provide supplemental instruction in laboratory class sessions, but there is increasing evidence that undergraduate TAs (UTAs) can fill an equivalent role. To quantitatively address this, we compared student performance in a series of two introductory biology classes and one third-year class and found that students with GTAs and UTAs leaders earn comparable final course grades. Additionally, both UTAs and GTAs are considered effective at encouraging a positive attitude toward science and fostering a positive laboratory environment, though the UTAs receive slightly higher scores on two of the assessments of attitude toward science. These results demonstrate that equally well-trained UTAs and GTAs have equivalently positive impacts on laboratory learners. Without diminishing the value of teaching by and for the GTA, this data demonstrates the comparable value of UTA laboratory educators.