Abstract The present article summarizes theory and data about symptomatology, epidemiology, and etiology of specific phobias. Additionally, the cognitive mechanisms involved in specific phobias are briefly discussed. By and large, the general pattern behind the development of specific phobias can be summarized as follows. Specific fears are highly prevalent among young children. In most children, these fears represent transitory phenomena. However, in a small sub-group of children, specific fears become chronic due to classical conditioning, modelling, and/or negative information transmission. Once a specific phobia has developed, it may be maintained by cognitive biases (i.e., attentional bias, covariation bias, and reasoning bias). Though specific phobias form a heterogeneous class of disorders, this pattern appears to be a good approximation. Nevertheless, several questions remain. For example, there is no ready explanation for the fact that specific phobias are more often diagnosed in women than in men. Similarly, it is not clear to what extent the nonrandom distribution of phobias can be interpreted in terms of cultural factors. Resolving these issues is not only important in its own right, but may have considerable heuristic value for our understanding of other anxiety disorders.