The literary achievements of the major Persian Sufi poet Farid ad-Din ‘Attar Nishapuri (1145/46-1221) ranges with the great poets of the turn of 12th and 13th century Sanai (d. 1131) and Jalal al-Din Rumi (d. 1273) in the history of classical Persian literature. However, the author of this article sets himself the task of presenting ‘Attar not as a poet, but as a thinker, who made a significant contribution to the development of Persian Sufism. The study is based on the analysis of the most important Attar’s poetical composition - “The Language of the Birds” ( Mantiq al-tayr ). Particular attention is given to the description of the categories and principles of theorizing, reflecting the philosophical approach to understanding reality. The author uses the methods of philological and textological analysis, the method of philosophical interpretation of the poetic text, identifying the relationship between specific poetic concepts and philosophical terms. The novelty of the research lies in the fact that it is representing systematically Attar’s philosophical views of for the first time in Russian philosophical Iranian studies. Analysis of the explicit references and the hidden allusions to specific concepts and the most important provisions of the Sufi doctrine, description of ‘Attar’s philosophical strategy and his understanding of philosophy, comparing ‘Attar’s views with the philosophical ideas of the major Sufi thinker Ibn ‘Arabi (1165-1240) allows the author to put ‘Attar’s philosophy into the context of Islamic medieval philosophical tradition.