The 10-item Appearance Anxiety Inventory (AAI; Veale et al., 2013) was developed to assess cognitive processes and behaviours characteristic of Body Dysmorphic Disorder (BDD). Although the AAI has a number of advantages for research and is widely used, the structure of it has only been evaluated in one previous study. The aim of this study was to conduct an independent evaluation of the AAI's factor structure and convergent validity. Two studies were conducted. Participants in Study 1 were 730 Australian university students (Mage = 21 years). Using exploratory and confirmatory factor analyses, results indicated that 9 AAI items loaded highly on a single factor. However, both the 9-item and the 10-item AAI had good reliability. In Study 2, the AAI 9-item measure was confirmed in a sample of 862 Australian adolescents (Mage = 13 years), and the results were compared to using the 10-item AAI. In each study, the 9-item AAI had excellent convergent validity with measures of body dysmorphic symptoms and appearance-based rejection sensitivity. The decision to use the 10 items of the AAI or to exclude the one item focused on “checking appearance (e.g., in mirrors)” to use a 9-item measure should depend on the research purpose.