This study aims to investigate the effectiveness of vocabulary learning strategies on Iranian EFL learners' vocabulary test score. To achieve this aim, fifty Intermediate level students from Kish English Institute were randomly selected from among fifteen classes after administering the Oxford Placement Test (OPT). Then, an intermediate level vocabulary test of 20 questions based on their class textbook named Total English was given to them. A questionnaire of vocabulary learning strategies (VLSQ) was, then, distributed among students to find out how each learner learned new vocabulary and in what way. Finally, the whole data gathered from OPT; vocabulary test and VLSQ were analyzed through SPSS by applying Chi-square and descriptive analysis. The findings showed a significant effect of vocabulary learning strategies on EFL learners' performance in a vocabulary test.