This paper investigates how headgear functions as a visual semiotic device to communicate social, spiritual, and cosmological hierarchies in the 18th-century murals of Karapitiya Temple, Sri Lanka. Focusing on the continuous narrative sequence depicting the life of the Buddha, the study isolates headgear as a key visual signifier through which muralists—hereditary artisans (Sittaru) trained within the ritualized craft lineage of the Kandyan period (ca. 1469–1815)—differentiated between kings, monks, laypersons, dancers, deities, and the Buddha. Rather than individual artworks, these murals are approached as codified design systems embedded in a ritualized visual tradition shaped by Buddhist cosmology and social order. Adopting a visual semiotic framework, the study applies a multi-stage methodology involving photographic documentation, iconographic extraction, contour drawing, proportional measurement, and typological classification of over 40 character depictions. The analysis reveals a structured visual grammar: elaborate crowns with high head-to-headgear ratios signify royal or divine authority; simplified forms or bare heads index humility or renunciation; and the Buddha is elevated through compositional scale and radiant centrality, rather than ornamentation. By decoding this system, the study demonstrates how a single visual element—headgear—encapsulates layered symbolic meaning. The findings reposition Kandyan murals as indigenous communicative frameworks that served pedagogical, political, and cosmological functions. This research contributes to culturally rooted design discourse, offering methodological tools for heritage visualization, postcolonial design education, and the reinterpretation of non-Western visual knowledge systems.