Background Meditation, including Mindfulness-Based Interventions (MBI), is a required Complementary and Integrative Health intervention at the US Department of Veterans Affairs (VA). Training VA clinicians to provide MBI at scale must address fidelity concerns and the assessment of clinician competency. Objective The psychometric properties of the Mindfulness-Based Intervention: Teaching Assessment Criteria (MBI:TAC), a widely used tool for assessing facilitator competence, continue to be explored. To support the dissemination of MBI, the utility of using the MBI:TAC for self-assessment for clinicians in a national training program was evaluated. Methods In a training cohort of VA clinicians (n = 39), participant self evaluations on 2 domains of the MBI:TAC are compared to the competency scores of 2 expert evaluators as based on the observations of a 10-minute exercise. Additionally, the inter-rater reliability between the 2 experts was explored. Results Intraclass Correlation for the 2 expert evaluators for Guiding Practice was significant ( ρ = .83, P = .003), but was not significant for Embodiment of Mindfulness (ρ = .34, P = .186). Self-evaluation scores were not significantly correlated to expert rater scores such that participants rate their level of competence higher than expert scores. Conclusion The MBI:TAC, while an essential tool in teacher training, may not produce accurate scores when used for self-assessment. Instruction from a senior teacher is needed for accurate scoring. Interrater reliability may be improved with enhanced domain operationalization and training. Implications for MBI training are explored.