Knowing that grades can have long-term consequences for students, teachers voice concern about being fair in the grading process. However, their interpretations of fairness are varied and sometimes contradictory. This study looked at how teachers in one standards-based educational system determined secondary students' grades, focusing specifically on the extent to which they followed a specific set of principles for grading. The results support previous research, and suggest that a better understanding of essential principles is needed for grades to accurately reflect students' achievement. (Contains 4 tables.)