Investigating the learner variables involved in second language (L2) listening comprehension can lead to a better understanding of the difficulties that learners may encounter while listening to an L2. In this line, this study aimed to examine the roles of some important learner variables (i.e., general language proficiency, aural vocabulary knowledge, and the metacognitive awareness) in L2 listening comprehension. To this end, 100 lower-intermediate Iranian learners of English were selected. Three tests (i.e., Oxford Placement Test, Aural Vocabulary Knowledge Test, and a listening comprehension test) were administered to the participants. A translated version of Metacognitive Awareness Listening Questionnaire (MALQ) was also used to measure the participants' metacognitive awareness in L2 listening. Results of Pearson correlations and hierarchical multiple regression analyses showed that of the variables examined, aural vocabulary knowledge was the strongest correlate with L2 listening and was also the most valuable in predicting variance in L2 listening comprehension scores (r = 0.46, p < 0.05) ([beta] = 0.40, p < 0.01), while metacognitive awareness correlated weakly with L2 listening.