Specific phobia and social anxiety disorder (SAD) share a number of features, but the focus of fear distinguishes between these anxiety disorders. In specific phobia, the excessive fear is focused on a particular situation or object, whereas in SAD, it is focused on one or more social and performance situations in which the individual fears acting in a way that will be embarrassing or lead to negative evaluation by others or revealing unbecoming personal attributes. The chapter focuses on the assessment of specific phobia and SAD in adults. It begins with a review of the nature of the disorders, which is followed by a review of clinical assessment instruments designed for the assessment purposes of (a) diagnosis, (b) case conceptualization and treatment planning, and (c) treatment monitoring and evaluation. Recommendations are included for instruments with the greatest scientific support and for assessing these anxiety disorders in a clinically sensitive manner.