The current study presents an approach for empirically identifying tailoring variables at midtreatment of cognitive behavioral therapy (CBT) protocols for youth with anxiety disorders that can be used to guide moves to second-stage treatments. Using 2 independent data sets (Study 1 N = 240, M age = 9.86 years; Study 2 N = 341; M age = 9.53 years), we examined treatment response patterns after 8 sessions of CBT (i.e., CBT midtreatment). We identified and replicated 3 classes of response patterns at CBT midtreatment: Early Responders, Partial Responders, and Nonresponders. Class membership at CBT midtreatment was predictive of outcome at CBT posttreatment. Receiver operating characteristics curves were used to derive guidelines to optimize accuracy of assignment to classes at CBT midtreatment. These findings support the promise of treatment response at CBT midtreatment to identify tailoring variables for use in abbreviating first-stage treatments and facilitating moves to second-stage treatments.