This chapter reviews effective ways of training therapists to competency. Adult learning models from which training methods have been derived are outlined. Methods combining both didactic and active learning styles such as case-based supervision, role-plays and reflection have been found to be most effective. Training competencies specific to the use of Cognitive Behavioral Therapy (CBT) in depression, anxiety, and children are examined. Finally, obstacles to effective training and to sustainable implementation of CBT in non-academic settings are discussed. Attitudes of therapists toward CBT, lack of access to training and supervisors, lack of organizational support for implementation, and therapists’ level of competence can all pose challenges.