This study attempted to investigate the effects of cultural background knowledge on vocabulary learning through reading culturally oriented texts. The study was conducted with 150 upper-intermediate male ( n = 75) and female ( n = 75) EFL students. The participants of each gender were randomly assigned into three equal groups: group A (Target Culture = TC), group B (Source Culture = SC) and group C (Culture-Free = CF). After homogenizing the participants through a researcher-made vocabulary pretest, three groups received the treatment which was reading comprehension materials reflecting a particular culture. During the treatment, some reading passages related to American and English cultures, Persian culture, and culture free materials were taught to group A, group B, and group C, respectively. At the end of the study, a researcher-made vocabulary posttest was administered. Results of one-way ANCOVA and paired samples t test revealed the significant effects of cultural familiarity whereby vocabulary gains were greater after participants read within the culturally oriented text. Moreover, the results showed that there was no significant difference in vocabulary knowledge posttest between male and female learners.
