Open science is a collection of actions designed to make scientific processes more transparent and results more accessible. Its goal is to build a more replicable and robust science; it does so using new technologies, altering incentives, and changing attitudes. The current movement toward open science was spurred, in part, by a recent series of unfortunate events within psychology and other sciences. These events include the large number of studies that have failed to replicate and the prevalence of common research and publication procedures that could explain why. Many journals and funding agencies now encourage, require, or reward some open science practices, including pre-registration, providing full materials, posting data, distinguishing between exploratory and confirmatory analyses, and running replication studies. Individuals can practice and promote open science in their many roles as researchers, authors, reviewers, editors, teachers, and members of hiring, tenure, promotion, and awards committees. A plethora of resources are available to help scientists, and science, achieve these goals. Keywords: data sharing, file drawer problem, open access, open science, preregistration, questionable research practices, replication crisis, reproducibility, scientific integrityThanks to Brent Donnellan (big thanks!), Daniël Lakens, Calvin Lai, Courtney Soderberg, and Simine Vazire OPEN SCIENCE 3 Open Science When we (the authors) look back a couple of years, to the earliest outline of this chapter, the open science movement within psychology seemed to be in its infancy. Plenty of people were pointing to problems in psychology research, collecting archival data to support the claims, and suggesting how science could be improved. Now it seems that the open science movement has reached adolescence. Things are happening-and they are happening quickly. New professional organizations are being formed to uncover and facilitate ways to improve science, often through new technology, and some old organizations are adopting new procedures to remedy problems created by past practices, often involving revising journal policies. Researchers are changing the way they teach, practice, and convey science. And scientific information (and opinions) are traveling fast. In blogs, tweets, Facebook groups, op eds, science journalism, circulation of preprints, post-print comments, video talks, and so on, more people are engaged in communicating science, and hoping to improve science, than ever before. Thus, any new technology, new procedure, new website, or new controversy we describe is likely to be superseded (or solved) even by the time this chapter is published. But the core values of open science should remain. The "Open Science" MovementScience is about evidence: observing, measuring, collecting, and analyzing evidence. And it is about evidence that can be shared across observers and, typically, although not necessarily exactly (Merton, 1973;Popper, 1959), replicated later. Science is about testing hypotheses, using inductiv...