This research explores the grammatical and semantic dimensions of the vocative style in Imam Al-Shafi‘i’s Diwan, emphasizing its significance as a core linguistic device in Arabic communication that shapes meaning and deepens emotional resonance. The study analyzes the various forms of vocative expression—particularly the particles yā, ayā, and the omitted vocative marker—within their syntactic structures and semantic contexts. It demonstrates how Al-Shafi‘i employed the vocative not merely as a grammatical form, but as a powerful artistic tool serving multiple purposes, including invocation, self-address, and moral exhortation. Through a systematic examination that integrates grammatical analysis with semantic interpretation, the research highlights how the vocative form reflects the poet’s religious and ethical vision while reinforcing the stylistic and emotional texture of his poetry. The findings affirm that the vocative in Al-Shafi‘i’s poetry functions as a central expressive mechanism, rather than a peripheral one, and the study recommends further exploration of other imperative sentence types and lexical semantics within his poetic corpus.