This paper discusses the meaning and range of replication in L2 research from both quantitative and qualitative perspectives. In the first half of the paper, it will be argued that key quantitative studies need to be replicated to have their robustness and generalizability tested and that this is a requirement of scientific inquiry. Such research is seen as a useful way of examining previous outcomes and of introducing novice researchers to the research process and academic discourse. The L2 writing field is seen to present an increasingly diverse nature of scope and topics, which can easily result in conflicting, fragmented, and consequently confusing research outcomes. Replication can help bring some order to this situation by focusing on the "why" of previous findings. In the second half of the paper, we extend our discussion to qualitative research, where the idea of replication is seen as inherently problematic. While recognizing the important differences between quantitative and qualitative research in this respect, we argue that an outright rejection of the concept of replication may have diverted attention away from considering ways in which qualitative research projects can build on one another and contribute to a developing understanding of L2 writing. Our arguments are based on developments in qualitative research methods and online technologies over the last quarter of a century, which undermine traditional objections to replication. We also propose using links to different types of related studies ("Reference Studies") as a means of making essential connections among related projects.