Ibrahim ibn Sinan (Arabic: Ibrāhīm ibn Sinān ibn Thābit ibn Qurra, ابراهيم بن سنان بن ثابت بن قرة; born 295-296 AH/c. 908 AD in Baghdad, died: 334-335 AH/946 AD in Baghdad, aged 38) was a mathematician and astronomer belonging to a family of scholars who originally hailed from Harran in northern Mesopotamia. He was the son of Sinan ibn Thabit (c. 880–943) and the grandson of Thābit ibn Qurra (c. 830–901). Like his grandfather, he belonged to a religious sect of star worshippers known as the Sabians of Harran.