Faridoddin Abu Hamed Mohammad Attar Nishapuri (Persian: فریدالدین ابوحامد محمد عطار نیشابوری; c. 1145 – c. 1221), better known by his pen-names Faridoddin (فریدالدین) and Attar of Nishapur (عطار نیشاپوری), or simply Attar (meaning apothecary), was a Persian poet, theoretician of Sufism, and hagiographer from Nishapur who had an immense and lasting influence on Persian poetry, on poet Rumi, and on Sufism. He wrote a collection of lyrical poems and number of long poems in the philosophical tradition of Islamic mysticism, as well as a prose work with biographies and sayings of famous Muslim mystics. The Conference of the Birds, Book of the Divine, and Memorial of the Saints are among his best known works.

Information about Attar's life is scarce and has been mythologised over the centuries. However, Attar was born to a Persian family and he practised the profession of apothecary, and personally attended to a very large number of customers. He is mentioned by only two of his contemporaries, Aufi and Tusi. However, all sources confirm that he was from Nishapur, a major city of medieval Khorasan (now located in northeastern Iran), and according to Aufi, he was a poet of the Seljuk era.

According to Reinert: It seems that he was not well known as a poet in his own lifetime, except at his home town, and his greatness as a mystic, a poet, and a master of narrative was not discovered until the 15th century. At the same time, the mystic Persian poet Rumi has mentioned: "Attar was the spirit, Sanai his eyes twain, And in time thereafter, Came we in their train" and mentions in another poem:

Attar travelled through all the seven cities of love

While I am only at the bend of the first alley.

Attar was probably the son of a prosperous chemist, receiving an excellent education in various fields. While his works say little else about his life, they tell us that he practised the profession of pharmacy and personally attended to a very large number of customers. The people he helped in the pharmacy used to confide their troubles in Attar and this affected him deeply. Eventually, he abandoned his pharmacy store and travelled widely - to Baghdad, Basra, Kufa, Mecca, Medina, Damascus, Khwarizm, Turkistan, and India, meeting with Sufi Shaykhs - and returned promoting Sufi ideas. Attar was a Sunni Muslim.

From childhood onward Attar, encouraged by his father, was interested in the Sufis and their sayings and way of life, and regarded their saints as his spiritual guides. At the age of 78, Attar died a violent death in the massacre which the Mongols inflicted on Nishapur in April 1221. Today, his mausoleum is located in Nishapur. It was built by Ali-Shir Nava'i in the 16th century and later underwent a total renovation during the rule of Reza Shah in 1940.

The thoughts depicted in Attar's works reflect the whole evolution of the Sufi movement. The starting point is the idea that the body-bound soul's awaited release and return to its source in the other world can be experienced during the present life in mystic union attainable through inward purification. In explaining his thoughts, Attar uses material not only from specifically Sufi sources but also from older ascetic legacies. Although his heroes are for the most part Sufis and ascetics, he also introduces stories from historical chronicles, collections of anecdotes, and all types of high-esteemed literature. His talent for perception of deeper meanings behind outward appearances enables him to turn details of everyday life into illustrations of his thoughts. The idiosyncrasy of Attar's presentations invalidates his works as sources for study of the historical persons whom he introduces. As sources on the hagiology and phenomenology of Sufism, however, his works have immense value.