Distress Intolerance (DI), defined as the perceived inability to tolerate negative mood states and experiential discomfort, has been posited as a vulnerability factor for several anxiety and emotional disorders. There is a relative paucity of research on DI in youth samples, in large part due to the absence of a psychometrically sound measure of DI in youth. The current study evaluated the psychometric properties of the Distress Intolerance Index for Youth (DII-Y) and the Distress Intolerance Index for Youth–Parent Report (DII-Y-P), which are downward extension adaptations of the adult-oriented Distress Intolerance Index (McHugh and Otto Behavior Therapy 43(3), 641–651, 2012). Participants were 176 youth (ages 9–17) and their parents who were seeking treatment for child anxiety problems. The DII-Y and DII-Y-P demonstrated good-to-excellent internal consistency. Convergent validity of the DII-Y and the DII-Y-P was supported by large, significant associations with measures of intolerance of uncertainty, as well as with anxiety sensitivity in the case of the DII-Y. Discriminant validity of the DII-Y and the DII-Y-P was supported by the absence of significant direct relationships with a measure of defiant behavior. Results support the use of DII-Y and DII-Y-P as reliable and valid instruments for the assessment of youth DI, providing a practical and efficient tool to study DI as a potential factor in the etiology and maintenance of youth anxiety and emotional disorders.