Dissemination and use of cognitive behavioral therapy (CBT), the primary evidence-based psychosocial treatment for pediatric anxiety disorders, in school settings has been slow, occurring primarily in the context of randomized controlled trials (RCT). No data are available on the sustained use of CBT by school clinicians after research support ends. Filling this gap, the current study examined clinicians: (1) recall and attitudes toward a modular CBT (M-CBT), (2) sustained use of anxiety screening measures, (3) sustained use of M-CBT and modifications made, (4) perceived reasons and barriers to sustained use and (5) an exploratory examination of predictors of the sustained use of M-CBT. Participants included 43 school-based clinicians (77% of those originally trained in an RCT; 90% female, 73% White) who were contacted 3.43 years after their initial training to complete an online sustainability questionnaire. The results indicated that while most clinicians recalled and had positive attitudes about the M-CBT training (90%), 63% reported they continued to use M-CBT and a majority made modifications to the content, length and format. Predictors of the sustained use, based on 22 single predictor regression models, included greater perceived acceptability and benefits (for youth and clinicians) of the intervention and lower perceived difficulty of administering M-CBT components. Fewer administrative demands were also associated with greater sustained use. Findings suggest that additional efforts are needed to enhance the sustained use of M-CBT for anxiety in school settings. Targeting specific aspects of the intervention materials (difficulty, benefits) as well as lowering administrative demands might facilitate the sustained use of M-CBT by school clinicians. [For the corresponding grantee submission, see ED608025.]