This study analyzed policies and countermeasures to remove barriers hindering the improvement of energy efficiency in designated buildings under the framework of Thailand's Nationally Appropriate Mitigation Actions (NAMAs). The study was conducted by means of literature reviews and interviews with relevant Thai officials. It was found that while Thailand has addressed energy efficiency in the designated buildings through ministerial regulations together with voluntary programs and financial instruments, the strength of the regulations is insufficient to enhance the compliance of dispersed energy end-users due to limitations in the monitoring mechanism. A number of barriers are interrelated, making them difficult to conduct stringent measurement, reporting, and verification (MRV), monitoring of the implementation measures. The establishment of a precise institutional management mechanism for MRV is required to collect the necessary baseline information, formulate policies, and disseminate them with a view to positively influencing the implementation of countermeasures to facilitate the NAMAs toward 2020.