This study aims to investigate the role of corrective feedback and negotiation of meaning within an Interactionist Approach (Long, 1996) in native speaker-Second Language learner and L2 learner-L2 learner interactions. While negotiation of meaning (NoM) and corrective feedback (CF) between native and nonnative speakers has been shown to be helpful for the nonnatives, it remains unclear whether CF and NoM between learners of equivalent or different proficiency produce greater negotiation of meaning and successful uptake of corrective feedback compared to the more traditional native-nonnative interaction. The key issue in this study is whether CF and NoM in different interactional combinations of interlocutors make a difference, in quantitative and qualitative terms. The study adopts a pretest-treatment-posttest design with six participants: two native English speakers, two Chinese L1 NNSs of high English proficiency level (NNS High) and two Chinese L1 NNSs of low English proficiency level (NNS Low). These informants generated 14 different dyads and produced 2377 turns while engaging in task-based interaction. By introducing the notions of group (i.e., NS-NNS versus NNS-NNS groups), combinations (e.g., NS-NNS High versus NNS High-NNS Low), and dyads, it is possible to compare results across groups, combinations and individuals. Results confirm that CF and NoM happen in NNS-NNS interaction yet they differ, qualitatively and quantitatively, according to the type of combination. Significantly, the best rate of success was obtained in the combination of learners with different proficiency levels i.e., the NNS High-NNS Low combination. In addition, error rates decreased from pre-test to post-test in all learners, especially NNS Low, which lends support to the notion that CF and NoM promote second language development also in interaction between learners.