This study tracked gender differential item functioning (DIF) on the English subtest of the Korean College Scholastic Aptitude Test (KCSAT) over a nine-year period across three data points, using both the Mantel-Haenszel (MH) and item response theory likelihood ratio (IRT-LR) procedures. Further, the study identified two factors (i.e. reading strategy and perceived interest) that explained a portion of the variance in the magnitude of gender DIF via a series of multiple linear regression analyses. The results indicated (1) an interaction between item type and gender DIF and (2) a significant relationship between gender differences in the examinee's perceived interest in test items and the magnitude of gender DIF. The study discusses the results based on previous DIF research and presents pedagogical implications and some avenues for further research. (Contains 8 tables.)