Traditional markets represent important cultural semiotic spaces where linguistic, visual, material, and spatial signs reflect social interaction, cultural identity, and local wisdom within community life. This study aims to examine the semiotic landscapes of traditional markets in Deli Serdang, Indonesia, focusing on how multimodal signs express and negotiate cultural identity and local wisdom. The study employed a qualitative semiotic approach grounded in Scollon and Scollon’s geosemiotics and Kress and van Leeuwen’s multimodal theory. The research was conducted in selected traditional markets in Deli Serdang Regency, North Sumatra, involving traders, buyers, and market administrators as participants. Data were collected through visual documentation, participant observation, in-depth interviews, and field notes. The analysis focused on market signage, vendor–customer interactions, spatial arrangements, and culturally significant artefacts. The findings reveal that traditional markets function not only as economic and communicative spaces but also as cultural texts that encode communal values such as reciprocity, mutual trust, and social cohesion. Identity negotiation is reflected through the use of vernacular languages, hybrid linguistic forms, and culturally embedded interactional practices that demonstrate continuity and adaptation amid modernization. Local wisdom is maintained through symbolic artefacts, ritualized practices, and moral values embedded in everyday market transactions. The study concludes that traditional markets in Deli Serdang constitute dynamic semiotic spaces that actively preserve cultural identity and local wisdom while strengthening cultural resilience and social harmony.