Kaysān (Arabic:کَيسان) is an Arabic name which literally means "smart" and "clever". Throughout history, different people were called Kaysan:
- Kaysan was the slave of Imam Ali (a) and he was martyred in the Battle of Siffin (37/657).
- Kaysan was the title or name of al-Mukhtar al-Thaqafi and Kaysaniyya are attributed to him. According to a narration, when al-Mukhtar was born, his father took him to Ali b. Abi Talib (a), Imam (a) cuddled him and call him "Kayyis" (Arabic: کَيّس; means: cunning) and he was called Kayyis then. Some believe Kaysan was the title of al-Mukhtar al-Thaqafi which was taken after the name of one his companion known as Abu 'Amra Kaysan.. Also some stated that when Muhammad b. al-Hanafiyya sent al-Mukhtar to avenge blood of Imam al-Husayn (a) to Iraq, he found him cunning and clever, then he called him Kaysan.
- Kaysan was one of al-Mukhtar's companion whose kunya was Abu 'Amra.
- Based on some sources he was Abu 'Amra Sa'ib b. Malik al-As'adi (d. 67/686).
- Some religious scholars believed the mentioned Kaysan was an unknown and fake person just like 'Abd Allah b. Saba'.
- The material for this article is mainly taken from کیسان in Farsi WikiShia.