Preprint version, accepted for publication 27 October 2021 In: Plonsky, L. (Ed.). Open Science in Applied Linguistics. John Benjamins kmcmanus@psu.edu Replication and Open Science in Applied Linguistics Research Kevin McManus, Penn State University, USA, kmcmanus@psu.edu Abstract This chapter addresses the role and place of replication research and open science practices in advancing theory building and new research directions in the field of applied linguistics. The chapter begins by describing what replication research is, what the most common types of replication study are, and why carrying out replication matters. Close attention is paid throughout to the ways in which replication benefits from and contributes to a variety of open science initiatives, including open materials, open access and preprints, and preregistration. 1. Introduction Interest, curiosity, and, to some extent, consensus about the role and place of replication research in the field of applied linguistics is growing (McManus, 2021). For example, some journals now include replication studies as a specific manuscript type (e.g., Applied Psycholinguistics, Language Teaching, Studies in Second Language Acquisition), workshops, summer schools, and book-length guides are helping researchers design and disseminate replication research (e.g., Porte & McManus, 2019), reviews of the field have synthesized current practices (e.g., Marsden et al., 2018), funding bodies are investing in the replication of influential studies (e.g., Dutch Research Council, Institute of Education Sciences), and professional organizations now include replication studies as highly-valued scholarly products in their guidelines for tenure and promotion (e.g., American Association for Applied Linguistics). At the same time, the field of