"Washback" refers to the influence of language testing on teaching and learning. This volume, at the important intersection of language testing and teaching practices, presents theoretical, methodological and practical guidance for current and future washback studies. In the field of language testing, researchers' major interest has traditionally been focused on issues and solving problems inherent in tests in order to increase their reliability and validity. However, the washback effect goes well beyond the test itself to include factors such as curriculum, teacher and learner behaviors inside and outside the classroom, their perceptions of the test and how test scores are used. Only recently have researchers started to empirically investigate the phenomenon of washback. This volume of such research serves two purposes by providing an overview of the complexity of washback and the various contextual factors entangled within testing, teaching and learning; and presenting empirical studies from around the world that offer insights into the effects of washback in specific educational contexts and models of research on which future studies can be based.