The present study examined the efficacy of online training (OLT), instructor-led training (ILT), and a treatment manual (TM) in training mental health clinicians in two core strategies of Dialectical Behavior Therapy (DBT): chain analysis and validation. A randomized controlled trial compared OLT, ILT, and TM among clinicians naïve to DBT (N = 172) who were assessed at baseline, post-training, and 30, 60, and 90 days following training. Primary outcomes included satisfaction, self-efficacy, motivation, knowledge, clinical proficiency, and clinical use. Overall, ILT outperformed OLT and TM in satisfaction, self-efficacy, and motivation, whereas OLT was the most effective method for increasing knowledge. The conditions did not differ in observer-rated clinical proficiency or self-reported clinical use, which both increased to moderate levels after training. In addition, ILT was particularly effective at improving motivation to use chain analysis, whereas OLT was particularly effective at increasing knowledge of validation strategies. These findings suggest that these types of brief, didactic trainings may be effective methods of increasing knowledge of new treatment strategies, but may not be sufficient to enable clinicians to achieve a high level of clinical use or proficiency. Additional research examining the possible advantages of matching training methods to types of treatment strategies may help to determine a tailored, more effective approach to training clinicians in empirically supported treatments.