Objective: The aim of this study was to investigate whether assimilation process of these expatriates in Indonesia e­ected their smile perception. Material and Method: Indonesian, British, and Korean lay people assessed smile esthetics perception on crown width, crown length, buccal corridor, gingival display, and smile arc. Extra oral photographs which consist of -ve components smile esthetics were digitally modi-ed into four di­erent categories. Smile esthetics perception assessed through visual analogue scale (VAS) by lay people who lived in Jakarta according to inclusive criteria. Results: In 95% CI, the normal category of all parameters, rated as the most aesthetic in smile perception by British, Korean, Indonesian raters. The sizes were Crown Width 8.5 cm, Crown Length 10 cm, Buccal Corridor 1.5 mm, Gingival Display 0.5 mm, and Smile Arc 0 mm. The least aesthetic were Very Wide Buccal Corridor, Very High Gingival Displays, and Smile Arc varies between groups. Conclusion: Normal category in all parameters was the most perceived aesthetically and given the highest rating by all groups. 95% CI VAS of British people's perception of smiles was the opinion that small, short and narrow were unesthetic, Korean people thought the opposite, while Indonesians people were in between. Regarding to assimilation process, perception of smile aesthetic seemed still related to the general opinion of the country origin. © 2025 JDMFS. Published by Faculty of Dentistry, Hasanuddin University. All rights reserved.