Background: Which instructor qualities do students consider most important? The answer likely depends on the student. This study attempted to trace beliefs about the most essential instructor qualities to students' academic achievement goals. Aims: The present study tested the hypothesis that students pursuing mastery goals favour instructors who stimulate and challenge them intellectually, whereas those pursuing performance goals favour instructors who present material clearly and provide clear cues about how to succeed. Sample: Participants were 157 students at a 4-year public university. Method: Participants designed the ideal professor through a hypothetical combination of nine widely valued instructor qualities, such as enthusiasm, presentation clarity, and an interactive teaching style. The more they acquired of any one instructor quality, the less they could acquire of the others, thus compelling students to distinguish necessary qualities from desirable luxury qualities. Results: Students' achievement goals corresponded to their views about the most essential instructor qualities. Mastery goals predicted greater demand for professors who intellectually challenge students and possess topic expertise, whereas performance goals predicted high demand for professors who present material clearly and provide cues about how to succeed in the course. Conclusions: The findings support emerging theorizing about how mastery and performance goals nudge students to pursue different learning agendas, with distinct consequences to their learning experience. (Contains 3 tables and 3 footnotes.)