After some years, vocabulary research has once again found its fundamental position in pedagogical studies as an inseparable component of language instruction. However, many studies conducted have focused more on vocabulary learning strategies rather than explicit instruction of these techniques. The present study, though, seeks to find out whether teaching vocabulary learning strategies is effective in enhancing the knowledge of EFL learners. Two vocabulary tests of Lex30 and Vocabulary Size Test were administered to 51 intermediate Iranian EFL learners. By employing a mixed method approach, five distinct semi-structured interview sessions were held. The results of independent samples t-tests revealed the effectiveness of teaching vocabulary learning strategies as the experimental group outperformed the control group. Moreover, the analysis of transcribed data suggested that learners showed positive attitude toward instruction of vocabulary learning strategies. Finally, some pedagogical implications for teaching vocabulary are offered.