© The Author(s) 2014. Anxiety vulnerability and dysfunction are characterized by an attentional bias to threat. Cognitive training procedures designed to modify selective attentional responding to threat originally were developed to test the hypothesis that this attentional bias causally contributes to anxious disposition. The capacity of attentional bias modification (ABM) training to alleviate dysfunctional anxiety has since attracted growing interest, and the present article reviews studies that have evaluated this therapeutic potential. When intended ABM training has successfully reduced attention to threat, it also has reduced anxiety vulnerability and symptomatology with a high degree of reliability. When the delivery of intended ABM training has not resulted in such anxiety reduction, this typically has reflected the failure to successfully modify attentional selectivity as required. We discuss ways in which ABM training procedures may be refined to optimize their capacity to reduce attentional bias to threat, to improve delivery of the resulting anxiolytic benefits.