The present study aimed at investigating whether vocabulary-learning strategies had any impact on the vocabulary learning of Iranian EFL learners. The participants of the study were 67 male and female undergraduate university students, majoring in English Translation and English Literature at Islamic Azad University, North Tehran Branch, who were taking “Reading Comprehension II” course. In order to ascertain that the participants were homogeneous in terms of their general language proficiency, a standardized proficiency test was administered. Subsequently, a standardized achievement test, which was prepared by the researchers based on the students’ course book, consisting of 60 items, was administered to the participants to examine whether they were familiar with the target words to be taught during the treatment. Throughout the four-month semester and during 20 sessions, the participants were instructed to focus on three vocabulary-learning strategies. The subjects in the first group were trained to use bilingual and monolingual dictionaries; those in the second group were taught to guess the meaning of new lexical items from the context; and the subjects in the third group were trained to use different texts to understand the meaning of words appropriately. In order to create the opportunity for the researchers to trace the vocabulary learning, a posttest, the same as the test used in the pretest, was administered to the participants of the study. Paired samples t-tests proved that using vocabulary-learning strategies had a positive impact on vocabulary learning in each of the groups. Additionally, the one-way analysis of variance (ANOVA) indicated a significant difference among the three groups. Finally, the result of Scheffé’s post hoc test showed that those participants who worked on text-specific activation strategy as a vocabulary learning strategy outperformed the subjects in the other two groups.