Khawaja Ahmad Yassawi or Ahmed Yesevi (Kazakh: Ахмет Ясауи, Arabic: أحمد يسوي, Uzbek: Ahmad Yasaviy, Аҳмад Ясавий, ئەحمەد يەسەۋىي; Axmet Yasawï, احمەت ياساۋئ; Turkmen: Ahmet Ýasawy, Ахмет Ясавы, آحمِت يَسَویٛ; Turkish: Ahmet Yesevi; born in Sayram in 1093, and died in 1166 in Turkestan City; both cities are now in Kazakhstan) was a Turkic poet and Sufi, an early mystic who exerted a powerful influence on the development of Sufi orders throughout the Turkic-speaking world. Yasavi is currently the earliest known Turkic poet who composed poetry in Middle Turkic. Ahmed Yesevi was a pioneer of popular mysticism, founded the first Turkic Sufi order, the Yasawiyya or Yeseviye, which very quickly spread over Turkic-speaking areas. He was an Hanafi scholar like his murshid, Yusuf Hamdani.
Yassawi's father was named Ibrahim. At age seven, when he was orphaned by the loss of his father, Yasawi was raised by another spiritual father, Arslan Baba. By age seven, Ahmad Yasawi had already advanced through a series of high spiritual stages and then, under the direction of Arslan Baba, the young Ahmad reached a high level of maturity and slowly began to win fame from every quarter. His father Shaikh Ibrahim had already been renowned in that region for performing countless feats and many legends were told of him. Consequently, it was recognized that, with respect to his lineage as well, this quiet and unassuming young boy, who always listened to his elder sister, held a spiritually important position.
Ahmad Yassawi later moved to Bukhara and followed his studies with the well-known Yusuf Hamdani. Upon the demise of Yusuf Hamdani, first ʿAbdullah Barki and then Hassan-i Andākī became the head of Hamdani's khanqah. Ahmad Yassawi became the head murshid of the Naqshbandi order when Hassan-i Andākī died in 1160. He then turned this position to Abdul Khaliq Gajadwani under Hamdani's advice and moved to Turkistan City in order to spread Islam in Turkestan.
Ahmad Yassawi made considerable efforts to spread Islam throughout Central Asia and had numerous students in the region. Yasawi's poems created a new genre of religious folk poetry in Central Asian Turkic literature and influenced many religious poets in the following countries. Yassawi made the city of Yasi into the major centre of learning for the Kazakh Steppe, then retired to a life of contemplation aged 63. He dug himself an underground cell where he spent the rest of his life. Turkish scholar Hasan Basri Çantay noted that "It was a Seljuk king who brought Rumi, the great Sufi poet, to Konya; and it was in Seljuq times that Ahmad Yesevi, another great Sufi, lived and taught. The influence of those two remarkable teachers has continued to the present." Yasavi is also mentioned by Edward Campbell (writing as Ernest Scott) as a member of the Khwajagan.
The Mausoleum of Khoja Ahmed Yasawi was later built on the site of his grave by Timur in Turkistan City. The Yasawi order tjat he founded continued to be influential for several centuries afterwards, with the Yasawi Sayyid Ata Sheikhs holding a prominent position at the court of Bukhara into the 19th century. There is the greatest influence of shamanistic elements in the Yasawiyya compared to other Sufi orders.
The first Kazakh-Turkish university, Ahmet Yesevi University, was named in his honor.
The Naqshbandi Idries Shah mentions Ahmed Yasavi's lineage in The Book of the Book. Yasawi Sufis are also present in Kashmir.
Yasawi's tomb was refurbished with a new structure by Timur.
Book of Wisdom (ديوان حكمت) (Dīvān-i Ḥikmet) was authored by Yassawi in Turkic. In 1905 and 1895 publishers published Yassawi's poems (Divan-i Khikmet) in Kazan.