This study investigated the effects of synchronous computer-mediated communication (SCMC) mode and interlocutor familiarity on frequency and characteristics of peer feedback in L2 interaction. Fifty dyads of EFL learners were equally assigned into familiar (+/--) groups and performed an interactive task in two SCMC modes (text/video-chats). After their interactions, they were interviewed individually about the impact of SCMC mode and interlocutor familiarity on the provision of feedback. Learners' text/video-chats were coded for feedback frequency and characteristics (e.g. type, linguistic focus, accuracy, and modified output). Results show that more instances of feedback were observed in the video- than text-chats; however, interlocutor familiarity did not affect the amount of feedback. Despite differences in types, feedback's linguistic focus and accuracy, frequency and characteristics of modified output were relatively similar between two SCMC modes. Content-based analyses of the interviews revealed that learners attributed the differences in feedback occurrence to various characteristics of the SCMC modes rather than interlocutor unfamiliarity. The results suggest greater benefits of the video-chat over the text-chat in promoting peer feedback and emphasise the importance of establishing a positive relationship among learners during L2 SCMC interaction.