This research aims to determine the level of policy implementation on teaching observation in Darasamutr School, Thailand. It likewise explored the factors affecting such level of implementation. Three population samples were considered for the study, namely elementary teachers, high school teachers and administrators. Perceptions among these sample groups on the level of policy implementation were statistically compared. Data collected from a total of 234 respondents revealed a consistent observation on the high level of policy implementation on teaching observation on the said campus. Significant differences however were noted along ethical protocols specifically between elementary teachers and administrators. The top three factors identified to be potently affecting the level of policy implementation were Teacher factor, Evaluation tool factor and Miscellaneous factor. Furthermore, some administrative challenges were identified by the administrator respondents. The study's conclusion points to some key areas along the implementation process needing review and revision. Relevant recommendations were then endorsed in order to facilitate optimal effectiveness and relevance of teacher evaluation. Finally, a concept map was drawn to highlight the proposed process flowchart for the campus implementation on teaching evaluation and observation.