ABSTRACT Thailand is a country where ethnic diversity and multilingualism are deeply embedded in the cultural landscape, and understanding the construction of ethnic identity provides crucial insights into its social dynamics. This study investigates how ethnic identities are constructed and negotiated through multimodal resources within the linguistic landscape of Ban Arunotai, a multiethnic village in Chiang Mai. Utilizing a comprehensive multimodal framework, the research analyzes how public signage combines linguistic, visual, auditory, and spatial elements to articulate and reshape identity. The findings reveal a hierarchical structure of languages and modes, where dominant languages are visually prioritized, while minority languages serve more localized, symbolic functions. Moreover, a shift from static, monolingual systems to fluid, multilingual repertoires among speakers reflects broader sociocultural changes shaped by translanguaging practices. By framing public signs as dynamic resources in the active formation and reinforcement of ethnic identities, this study offers significant implications for understanding identity politics and social integration in multilingual settings.