Despite the emphasis on threat appraisal in cognitive models of anxiety, self-report measures of related processes in children and adolescents have been lacking. This paper reports on the development and preliminary psychometric evaluation of a new measure of threat appraisal for children and adolescents – the Threat Appraisal Questionnaire for Children (TAQ-C). Based on current conceptualisations of threat appraisal, the TAQ-C was designed to index the construct across three dimensions: probability, cost, and coping difficulties. Confirmatory Factor Analysis was used to examine this structure in a community sample of n = 312 children (ages 9-15 years, 55% female). Results indicated that the scores on the instrument capture three factors (Probability, Cost and Coping difficulties). Moreover, a model in which the 1st-order factors loaded significantly on a single 2nd order factor of threat in general, was supported. The TAQ-C was found to demonstrate good internal consistency, and acceptable levels of test-retest reliability within a 3-4 week interval, when evaluated with a subsample of n = 51 children. Support for convergent validity was demonstrated, with TAQ-C scores found to correlate strongly with existing measures of child anxiety, and conceptually related cognitive processes. Divergent validity was also evidenced, with low correlations found between TAQ-C scores and the unrelated construct measure of Hyperactivity-Inattention. The TAQ-C, therefore, appears to be a promising measure with a range of potential applications for child and adolescent settings.