Muhammad ben Ahmad ben Idrīs ben husayn ben Qāsim ben Īsā al-hillī al-Ijlī , known as Ibn Idrīs al-hillī was an influential Imamiyyafaqih (jurisprudent) in late 6th/12th century. His maternal lineage is said to go back through three ancestors to al-Shaykh al-Tusi.

He was an expert in Islamic jurisprudence,usul al-fiqh (principles of fiqh), Quranic exegesis, and Arabic lexicology. Ibn Idris is known for his extensive use of rational reasons in the deduction of the laws of sharia, his unorthodox fatwas, and his breaking the widely sanctified, uncriticizable picture of al-Shaykh al-Tusi. He brought Islamic jurisprudence to a new stage by opening the way to criticize al-Shaykh al-Tusi's views. He had a sharp tongue criticizing other scholars, and for this he was criticized by some scholars. His main masters are Abu l-Makarim b. Zuhra and Ibn Shahrashub, and people such as Ibn Nama and al-Muhaqqiq al-Hilli's father were his pupils. His well-known and influential work is al-Sara'ir.

Ibn Idris died about 597/1200 but his son said, Salih, he died aboas maintained by some scholars (based on the mistake that Ibn Idris died in 577/1181. This is incompatible with what Ibn Idris himself said about the date of writing al-Sara'ir and with the fact that his pupil, Fakhkhar, has heard a hadith from him in 593 /1196. Ibn Idris died in Hillah. His mausoleum is located in the "Jami'ayn" district in Hillah.