Abu Ma'shar; Ja'far ibn Mu?ammad al-Balkhi (also known as al-Falaki or Ibn Balkhi; Latinized as Albumasar; Albusar; or Albuxar) (10 August 787 in Balkh; Khurasan - 9 March 886 in Wasi?; Iraq); was a Persian astrologer; astronomer; and Islamic philosopher; thought to be the greatest astrologer of the Abbasid court in Baghdad.

He was not a major innovator; and his works are practical books for training of astrologers; even as an astrologer he was not intellectually rigorous. Nevertheless; he wrote a number of practical manuals on astrology that profoundly influenced Muslim intellectual history and; through translations; that of western Europe and Byzantium.