Abū al-Faḍl Jaʻfar ibn ʻAlī al-Dimashqī;
(Arabic: أبو الفضل جعفر بن علي الدمشقي; fl. 12th-century) was a prosperous Muslim merchant from Damascus. He is best known for being the author of Kitab al-Isharah ila Mahasin at-Tijarah wa Marifat Jayyid al-Aʼrad wa Kadiiha wa Ghush-ush al-Mudallisin fiha (A Guide to the Merits of Commerce and to Recognition of Both Fine and Defective Merchandise and the Swindles of Those Who Deal Dishonestly).
Almost nothing is known about al-Dimashqi’s life. He was among the Muslim writers who were influenced by Greek sources, particularly by the neo-Pythagorean Bryson of Heraclea.