This study explores structuralist thinking in Sibawayh’s Al-Kitab in light of modern linguistic theory, aiming to trace how contemporary linguistics has been influenced by the Arabic linguistic tradition and to identify early structuralist foundations in Sibawayh’s work. Employing a structuralist analytical approach, the research investigates five linguistic levels: the phonological, lexical, syntactic, semantic, and symbolic. The analysis demonstrates how Sibawayh connected sound patterns to meaning formation, approached lexical items through relational semantics, penetrated deep syntactic structure in his treatment of grammatical rules, and examined semantic relations that organize meaning. At the symbolic level, the study highlights his ability to link language use to underlying structural patterns. The preface situates the study within the broader context of Western engagement with Arabic linguistic theory and the role of Sibawayh’s work in shaping early structuralist assumptions. The findings affirm the maturity of early Arabic linguistic thought, the significant influence of classical Arabic scholarship on modern linguistics, and the structural coherence of Al-Kitab, which emerges as a pioneering model of structural analysis. Through its multi-level examination, the study shows that Sibawayh anticipated several principles later formalized in modern linguistic theory.