Before the spread of Islam in the 7th century CE, the majority of Kurds practised their indigenous religions, today are referred to as Yazdanism. Yazidism and Yarsan, which may stemmed from and eventually replaced those religions are still practised among the Kurds. Most Yazidis live in Iraqi Kurdistan, in the vicinity of Mosul and Sinjar. Yazidis are also found in Syria, Armenia, Turkey, and Germany. Their holy book is "Mishefa Reş" (The Black Book). The Yarsan, or Ahl-e Haqq, religion is practised in western Iran, primarily around Kermanshah. There were also many Kurds who practised Zoroastrianism. 
Also before arrival of Islam in the 7th century AD there were large Kurdish populations practising Christianity, still found in small numbers especially in Iraqi Kurdistan. The Kurdish kingdom of Adiabene, including a large number of its Kurdish citizens, converted to Judaism during the 1st century BC. Rabbi Asenath Barzani, who lived in Mosul from 1590 to 1670 was among the very first Jewish women to become a Rabbi.
Malak Ta’us, the peacock angel of Yazidism religionIn the 7th century, Arabs conquered the Kurdish regions and converted the majority of Kurds to Islam. The majority of Kurds are Muslim, belonging to the Shafi school of Sunni Islam, distinguishing them in the region, (and to a much lesser degree, the Hanafi) Schools of Sunni Islam. There is also a significant minority of Kurds that are Shia Muslims, primarily living in the Ilam and Kermanshah provinces of Iran and Central Iraq ("Al-Fayliah" Kurds). The Alevis are another religious minority among the Kurds, mainly found in Turkey. There are also Kurds who are Agnostics.
Most Kurds have liberal tendencies toward religion, for instance Kurdish women usually do not wear hijab, do not cover their face and this differentiate them from Arab and Iranian women