The study of the individual learner differences including learner effectiveness has been a genuine concern for second language researchers. The present study strove to examine the impact of learner effectiveness on the language learners' learning strategy use. According to this purpose, first, the researchers developed the two-part 40-item learning strategy questionnaire of the study according to the strategy questionnaire developed by Wong and Nunan (2011). Second, they selected 441 students (224 male & 217 female) studying at the first year of their graduate program at universities in East Azerbaijan Province (Iran) as the participants of the study. Third, they administered the questionnaire of the study to the chosen participants and asked them to complete it. Finally, the researchers employed the chi-square test to analyze the collected data of the study. Based on the results of the study, there were significant differences between the more effective and less effective EFL learners' use of language learning strategies. On the basis of these results, it was argued that the syllabus designers should include specific parts in the teaching materials of the EFL classrooms in which the learners become familiar with various learning strategies and are trained to employ the most efficient strategies for the performance of language learning tasks. Similarly, it was pointed out that the EFL teachers should familiarize their learners with the diverse language learning strategies and their predominant role in the process of second language acquisition.