The development, reliability, and validity of a new instrument, the Social Phobia and Anxiety Inventory for Children (SPAI-C), is described. The results indicate that the SPAI-C has high test-retest reliability and internal consistency. In addition, an assessment of concurrent and external validity indicates statistically significant correlations with commonly used self-report measures of general anxiety and fears and parental reports of children's anxiety and social competence. The results of a factor analysis indicate that the scale consists of three factors: Assertiveness/General Conversation, Traditional Social Encounters, and Public Performance. Finally, scores on the SPAI-C successfully differentiate socially anxious and non-socially-anxious children. The instrument appears to be a reliable and valid measure for childhood social anxiety and fear and may prove useful for improving clinical assessment and documenting treatment outcome.