This study intended to inspect the possible effects of teaching English lexical clusters on speaking accuracy of Iranian EFL intermediate learners. Also it examined the influence of gender on the effect of teaching English lexical clusters on speaking accuracy of the same learners. 41 male and female EFL intermediate learners, studying English at intermediate level at Zabankade Institute in Tehran, were selected based on their performance on OPT test to 60 EFL learners. Then they were randomly assigned into two groups, as the experimental (n=21) and the control (n=20) groups in two classes. This study had a quasi-experimental design in which there were both a control and an experimental group, and the pretest and posttest were administered to collect data. First, a PET speaking test was administered to the participants of two groups to examine the initial knowledge of speaking grammatically of them. The experimental group of the study was treated with the teaching of English lexical clusters and the control group through a traditional method of teaching without lexical clustering technique. At the end of the experimental period, a posttest of PET speaking test identical to the pretest of PET speaking test was administered to the both groups of the study. In order to analyze the scores obtained from the pretest and posttest and answer the research questions of the study, a mixed between-within subjects ANOVA was applied. Time was the within-subject factor, and group and gender were considered as the between-subject factors. Tests of between-subjects effects (Table 7) indicated that there was a statistically significant effect for the Group (F(1,37)=6.04, P<.05, Eta square=.14) in speaking accuracy. Consequently, the first null hypothesis is rejected, and therefore, it can be claimed that teaching English clusters significantly improves Iranian Intermediate EFL learners speaking accuracy. Tests of between-subjects effects failed to find any statistically significant effect for Gender (F(1,37)=.99, P>.5, Eta square=.02) in speaking accuracy. So, the second null hypothesis was confirmed and it was revealed that gender does not affect the vocabulary performance of the same learners. This may have significant implications for language instructors, course book writers and learners to make more advancement in vocabulary learning and speaking accurately through employing vocabulary or lexical clustering as a technique. پرونده مقاله