The present study aims to examine how listening comprehension processes (top-down and bottom-up) differ by second language proficiency. To investigate such differences, experiments (listening tasks) followed by questionnaires and semi-structured interviews were conducted. Participants included 18 lower intermediate learners, 19 upper intermediate learners, and 23 advanced learners. Participants listened to materials under two conditions: (a) vocabulary knowledge; no background knowledge and (b) no vocabulary knowledge; background knowledge. Results showed that lower intermediate learners comprehended better in (a), whereas upper intermediate learners performed better in (b). No significant difference was observed between (a) and (b) for advanced learners.