Cognitive load plays an important role in learning, in general, and L2 listening comprehension, in particular. This study is an attempt to investigate the effect of metacognitive instruction (MI) and metacognitive instruction through dialogic interaction (MIDI) on L2 listeners’ cognitive load. Mixed method design with 60 participants of male and female Iranian advanced learners aged between 20 and 30 was used. Two experimental groups (n=20) received weekly interventions based on metacognitive instruction and metacognitive instruction through dialogic interaction for 10 sessions, respectively. The third or control group (n=20) had the same listening samples with regular procedure without the metacognitive intervention program in each session. The study used three different instruments: a) a modifed version of cognitive load questionnaire, b) digit span tests, and c) focused group interviews to investigate learners’ level of cognitive load throughout the process. The results testifed not only improvements in listening comprehension in MIDI but a radical shift of cognitive load rate within this group. In other words, listeners experienced the least cognitive load in MIDI compared with other groups.
