The Fin Garden of Kashan, as one of the most prominent examples of an Iranian garden, has a complex system of meaning that is formed in the interaction between natural elements, spatial organization, and the audience's perceptual experience. Despite numerous studies on the form, geometry, and symbolism of Iranian gardens, the precise mechanism of meaning production in these spaces, especially from the perspective of systematic semiotics, has been less systematically analyzed. The main issue of this research is to explain how the natural elements of the Fin Garden of Kashan function as signs and to examine how meaning is produced and established in the spatial organization of the garden based on Peirce's three-tiered semiotic framework. The aim of the research is to analyze the role of water, plants, earth, and pavilion as iconic, indexical, and symbolic signs and to explore the semantic relationships between them in shaping the audience's perceptual experience. The qualitative research method is descriptive-analytical, and the data were collected through documentary studies, theoretical source analysis, field impressions, images, and spatial documents, and analyzed with sign coding. The findings show that the natural elements of the Fin Garden operate simultaneously on three levels: iconic, indexical, and symbolic, and that meaning is not static, but rather a gradual and dynamic process that is formed during the audience's movement, observation, and reflection. Water and pavilions, as dominant signs, play a pivotal role in establishing meaning, while plants, earth, and paths, as reinforcing signs, provide the perceptual and spatial framework of meaning. Also, the inter-sign relationships and temporal dimension of the elements transform the Fin Garden into a living, multilayered text in which meaning is continuously reproduced. The results of the study show that the Fin Garden of Kashan is an outstanding example of the manifestation of Peirceian semiotics in Iranian landscape architecture.