Social scientists have long recognized that students’ course grades are consequential for academic progress, yet they have devoted little attention to variation in the protocols through which instructors assign grades. I call these protocols “grading practices.” Their variation may be especially wide in college settings, where instructors often have considerable discretion over grading practices. In some practices, grades are criterion-based, wherein student performance is compared against a set of standards. In other cases, students are compared to the performance of other students in a practice known as curving. Students entering higher education face the challenge of recognizing variation in grading practices and making sense of them under conditions they may perceive as high stakes. I report preliminary findings from a longitudinal study of undergraduates moving through an admissions-selective university to demonstrate the breadth of variation grading practices students encounter. I find substantial variation in how grades are assigned even among courses utilizing curved grades. Perhaps remarkably, initial analyses of qualitative interview data with students in courses with curved grades surface little evidence that grading curves per se engender competition; rather, perceptions of grades in curved courses are highly dependent on course structure and students’ previous exposure to course content.