Construct-irrelevant variance is considered as a major threat to validity which indicates the existence of additional unrelated variables that distort the meaning of test scores and cause the test to be biased. Differential item functioning (DIF) analysis is an important technique in examining the validity and fairness of educational tests. Concerning the importance of test fairness in large-scale exams, this study aimed to (1) detect gender DIF in the reading comprehension section of the B2 First exam using the Rasch model and Mantel-Haenszel method, and (2) investigate the comparability of results from the two DIF detection techniques. To this end, the reading section of the B2 First exam was administered to 207 undergraduate students of English as a foreign language (EFL). After checking the fit of the data to the Rasch model, the results of the Rasch model-based DIF analysis showed the presence of two items indicating DIF, whereas the results of Mantel-Haenszel showed that there were three gender-DIF items.