This article critically reviews the literature that examines the anxiety phenomenon in the field of second/foreign language learning. A major theme that runs through this review is how anxiety comes into play in second/foreign language learning, and whether it is a central construct or only an add-on element that is negligible. Anxiety is defined and described in how it is measured and relates to other affective concepts. Drawing on cognitive, curriculum, and cultural perspectives, the paper examines the possible causes and effects of language anxiety and the relationship between anxiety and second/foreign language learning. Possible educational implications of the anxiety research are indicated.