Many research universities rely on graduate students to supervise undergraduate research assistants (RAs) who collect data and handle research logistics. This experience can be mutually beneficial, as RAs receive hands-on learning, and graduate students practice mentorship in preparation for assuming a faculty role. However, assistantships must be intentionally designed to meet educational (not just practical) goals. What training and support do graduate students receive to take on this mentorship role? In two surveys, RAs reported on their satisfaction, educational benefit, and desired changes; while graduate students reported on their goals, challenges, and the support they receive.