Individuals with Williams syndrome (WS) exhibit striking social behaviour that may be indicative of abnormally low social anxiety. The present research aimed to determine whether social anxiety is unusually low in WS and to replicate previous findings of increased generalised anxiety in WS using both parent and self report.Fifteen individuals with WS aged 12-28 years completed the Spence Children's Anxiety Scale (SCAS) and the Children's Automatic Thoughts Scale (CATS). Their responses were compared to clinically anxious and community comparison groups matched on mental age. The findings suggest that WS is not associated with unusually low social anxiety but that generalised anxiety symptoms and physical threat thoughts are increased in WS, relative to typically developing children. Williams Syndrome (WS) is a genetic disorder caused by a microdeletion of a sequence of genes on chromosome 7. Prevalence is between 1 in 7,500 and 1 in 20,000 (Martin, Snodgrass, & Cohen, 1984;Stromme, Bjornstad, & Ramstad, 2002).The deletion typically results in dysmorphic facial features, short stature and a mild to moderate intellectual imapairment (Bellugi, Lichtenberger, Jones, Lai, & St, 2000;Mervis et al., 2000). Additionally, individuals with WS exhibit outgoing, gregarious social behaviour, as if they have little or no social anxiety (Doyle, Bellugi, Korenberg, & Graham, 2004;Jones et al., 2000). In contrast to this social behaviour, there is emerging evidence that individuals with WS may be at increased risk for Generalised Anxiety Disorder (GAD) and Specific Phobia (Dykens, 2003; Leyfer, WoodruffBorden, Klein-Tasman, Fricke, & Mervis, 2006). These findings may indicate that the WS deletion specifically increases risk for certain anxiety disorders whilst decreasing risk for Social Phobia. However, it is also possible that individuals with WS do experience social anxiety but that their outgoing social behaviour masks these thoughts and feelings of social anxiety. Due to the limitations of previous research, it is not currently possible to differentiate between these two hypotheses. The present study utilises a multi-method, multi-informant approach to examine the evidence that social anxiety is unusually low in WS.Although a number of early studies reported that WS is associated with increased anxiety (Davies, Udwin, & Howlin, 1998;Einfeld, Tonge, & Florio, 1997;Sarimski, 1997), there has been little examination of specific subtypes of anxiety (e.g. (2006) found evidence of high rates of GAD (12%) and Specific Phobia (54%) in children with WS, relative to rates reported for typically developing children, and also reported that 1.7% of their sample met criteria for Social Phobia. Similar prevalence rates for GAD and Specific Phobia were found by Dodd & Porter (in press) for a sample of children and adults with WS, however, no cases of Social Phobia were found. By comparing these prevalence rates to those reported for typically developing children (for example, Bolton et al., 2006;Costello et al., 1996), it is clear ...