Sultan Sahak (Persian: سلطان سهاک, translit. Soltân Sahâk; (born 14th century; died 15th century) was a Kurdish religious leader of Arab descent who founded the spiritual path of the Ahle Haqq, also known as the Yarsan. He is considered to be the manifestation that fully reflects the divine essence by the Ahle Haqq and revealer/expounder of the fourth stage of the religion.
Sultan Sahak was born in Barzanjeh, which is in the province of present-day Sulaymania, Northern Iraq. According to the Ahl-e Haqq hagiography, he was a direct descendant of the Shia Muslim Imam Musa Kazim. Later on his life, he moved to the Avroman region in Iran. His father, Shaykh Isi, was a Shia religious leader with Sufi inclinations and his mother, Khatun-e Razbar, is considered the manifestation of one of the seven archangels. As with Jesus, the birth of Sultan is also believed to have been a case of virgin birth. According to his followers he revealed the fourth stage of the religion (Haqiqat=truth) to earth, the Bayabas-e Pirdiwari (beyond the bridge). According to the Ahl-e Haqq hagiography, the Asian conqueror Timur (Tamerlane) once met with Sultan and used him as an oracle. Sultan Sahak died in the village of Sheykhan in Kermanshah Province where his tomb remains a place of pilgrimage for his followers. 
Sultan Sahak's teachings were recorded by his disciples and later published in the Gurani language as the Kalam-e Saranjam. He is given various names by the followers of the Ahl-e Haqq, including Shah-e Haqiqat (the King of Truth), Saheb-Karam, Saan Sahaak and Khwaavandekaar (Lord).
Sultan Sahak revealed several principles that constitute the core belief of the Ahl-e Haqq mystical sect:
- The four pillars of the fourth stage (the stage of the Truth or Haqqiqat): purity (pāki), rectitude (rāsti), self-effacement (nisti), and self-abnegation (redā).
- The partial or total manifestation of the divine essence in human form.
- The guidance from the arch-angel Gabriel for all those who want to reach the truth
- The seven arch-angels, who were the first creations of the highest rank and who perform missions to guide humanity.
- The divine hierarchy, which constitutes the saviours, who manifest themselves on earth and other planes
- The principle of ascending successive lives for the process of perfection
- Kehl-Bodrogi, Krisztina; Barbara Kellner-Heinkele; Anke Otter-Beaujean, eds. (1997). Syncretistic Religious Communities in the Near East. Brill Publishers. p. 105. ISBN 90-04-10861-0. Partial text at Google Books.
- Elahi, Bahram (1987). Path of Perfection, the Spiritual Teaching of Master Nur Ali Elahi. ISBN 0-7126-0200-3.
- Elahi, Nur Ali. Burhan al-Haqq, (1963 first edition), Library of Congress call number BP195.A4 I42 1963 - card number:75-284686. Excerpt from pg 42 in original Persian: نسبش بحضرت امام موسی کاظم(ع) میرسد، محل تولدش قریۀ (برزنجه) ناحیۀ (شاره زور) بخش (حلبجه) شهرستان (سلیمانیه) استان (کرکوک) کشور فعلی عراق است.
- Hamzeh'ee, M. Reza (1990). The Yaresan: A Sociological, Historical and Religio-Historical Study of a Kurdish Community. ISBN 3-922968-83-X.