This main aim of this study is to understand challenges resulting from Thai police's performance with respect to counterterrorism and counter-terrorism cooperation between ASEAN and Thai police. Moreover, this study attempts to formulate appropriate guidelines with a view to develop and strengthen counter-terrorism cooperation between Thai police and ASEAN region. For this reason, the present study employs a qualitative research design. The researcher employed in-depth interviews with 50 samples including police officers, scholars, and diplomats. It is revealed that problems of Thai police’s operations on counter terrorism were caused by both external and internal factors. One such external factor is the inadequate level of cooperation between regions such as non-sharing of information and mutual respect principles. These are key challenges for counter-terrorism operations of the Thai polices. In terms of internal factors, it is found that Thai police officers lacked knowledge and understanding of counterterrorism and foreign language skills. As a result, the current research recommends that knowledge of counterterrorism be improved, and police officers be urgently trained and taught foreign language communication skills. This study fills several existing theoretical and practical gaps discussed below. Findings from the study provide valuable insight for policymakers in the Thai policing system.