This study examined associations among children’s anxiety, interpretation bias, and anticipated distress before and after cognitive behavioral therapy (CBT) and investigated baseline levels of interpretation bias and anticipated distress as well as changes in these cognitive biases following treatment as predictors of treatment outcome. Clinically anxious youth (N = 39) were treated with brief CBT augmented with a smartphone app. Children completed measures assessing their anxiety, interpretation bias, and anticipated distress at baseline, post-treatment, and 2-month follow-up. Children’s anxiety, interpretation bias, and anticipated distress significantly decreased following treatment. Anticipated distress was associated with higher anxiety at all time points; however, interpretation bias was not significantly associated with anxiety before or after treatment. Reductions in anticipated distress following treatment predicted concurrent and prospective reductions in anxiety. Reduced anticipated distress following treatment may contribute to enhanced treatment outcomes and may be more strongly related to the maintenance of youth anxiety than interpretation bias.