Reports of exaggerated anxiety and physiological hyperreactivity to social-evaluative situations are characteristic of childhood social phobia (SP). However, laboratory research on subjective, autonomic and endocrine functioning in childhood SP is scarce, inconsistent and limited by small sample sizes, limited breadth of measurements, and the use of non-standardized stressor tasks. We exposed 8-12-year-old children with DSM-IV SP (n = 41) and matched healthy control children (HC; n = 40) to the Trier Social Stress Test for Children (TSST-C) while measuring subjective anxiety, heart rate (HR) and salivary alpha-amylase (sAA) as well as salivary cortisol. The SP children showed heightened reactivity to the TSST-C on subjective anxiety compared to the HC children but not a heightened reactivity in HR, sAA or cortisol. However, the SP children showed chronically elevated HR levels throughout the whole laboratory session. Whereas subjective anxiety seems to respond specifically to social-evaluative stress in childhood SP, HR levels may be chronically elevated suggesting a more generalized autonomic hyperreactivity.