Transdiagnostic models of psychopathology suggest that disorders may share common features that could influence their severity. Attention problems and psychomotor restlessness are included in the diagnostic criteria for several disorders, including disorders on the internalizing spectrum, but their transdiagnostic significance has received little attention. We identified patterns of attention problems and restlessness among clinic-referred youth (N = 142; age 11-18) with internalizing problems, in order to understand their clinical significance in terms of internalizing symptom severity and response to cognitive behavioral therapy (CBT). A latent class analysis was used to identify patterns of self-reported attention problems and psychomotor restlessness, and classes were compared on internalizing, depression, and anxiety severity. Differences in treatment response were examined in a subset of youth (n=82; age 14-18) who participated in group CBT. Youth in the Attention Problems class (42% of sample) and youth in the Restless class (15% of sample) endorsed significantly more internalizing, depression, and anxiety problems than youth with Low Symptoms of attention problems or psychomotor restlessness (43% of sample). Youth in the Restless class responded significantly better to CBT than youth in the Low Symptoms of attention problems or psychomotor restlessness class in terms of decrease in overall internalizing problems. Attention problems and psychomotor restlessness appear to be important transdiagnostic markers of severity across the internalizing spectrum; however, they do not limit the effectiveness of CBT and, in the case of psychomotor restlessness, may forecast a good treatment response.