The aim of the study was to examine the relationships between achievement emotions, epistemic curiosity, and graded performance regarding English courses of undergraduate students in English preparatory classes. Exploratory correlational design was adopted in the study. A total of 475 undergraduate students in English preparatory classes voluntarily participated in the study. The findings showed that graded performance regarding English courses was significantly and positively predicted by both curiosity as a feeling of deprivation and curiosity as a feeling of interest. The findings also showed that graded performance regarding English courses was significantly, yet negatively predicted by anxiety and boredom.