This study, with a scientific and critical approach, analyzes various types of deviations from norms present in the masnavis of Mantiq al-Tayr, Ilahi-Nama, Musibat-Nama, and Asrar-Nama, and examines both the quantity and quality of their application. Literature, as a linguistic art, plays a significant role in capturing the attention of its audience. The aim of this research is to investigate linguistic deviations from norms in the masnavis of Attar of Nishapur. Literary language is shaped through deviation from the ordinary norms of language, and such linguistic deviations can contribute to enhancing the impact of literature. Although the concept of deviation from norms is a relatively modern discussion within the Formalist school, the essence of literature has always been intertwined with such linguistic deviations. In this context, Attar of Nishapur, by employing different forms of semantic, syntactic, and phonological deviations, has succeeded in foregrounding and enhancing the literariness of his poetry. Semantic deviation includes the creation of poetic images through simile, metaphor, personification, and metonymy, which bestow a poetic quality upon the poet’s language. Furthermore, due to the necessity of meter and musicality, Attar resorts to syntactic deviations, and for the sake of defamiliarization and creating strangeness in expression, he employs phonological deviations. The use of archaic and obsolete vocabulary is also a prominent feature of his poetry. Although dialectal deviation is less pronounced in his works, words from the Nishapuri dialect and other dialects of Khorasan are evident in his poetry.