(Σιβύρτιος), a Macedonian officer in the service of Alexander the Great, who was appointed by him, on his return from India (B. C. 326), governor of the province of Carmania. This post he shortly after exchanged for the more important satrapy of Arachosia and Gedrosia, to which he succeeded on the death of Thoas (Arrian, Arr. Anab. 6.27; Curt. 9.10.20). At the death of Alexander, Sibyrtius, in common with most of the other governors of the remote eastern provinces, retained possession of his satrapy, which was again confirmed to him in the second partition at Triparadeisus, B. C. 321 (Diod. 18.3; Justin, 13.4 ; Arrian, apud Phot. p. 71b.; Dexippus, ibid. p. 64b.). In the subsequent divisions which arose among the eastern satraps, Sibyrtius was one of those who supported Peucestes against Python and Seleucus, and afterwards accompanied that leader when he joined Eumenes in Susiana, B. C. 317. His attachment was, however, to Peucestes, and not to Eumenes, and in the intrigues of the former against his commander-in-chief, Sibyrtius supported him so strongly that he incurred the especial resentment of Eumenes, who threatened to bring him to trial; a fate from which he only escaped by a hasty flight. But this open rupture with Eumenes had the advantage of securing him the favour of Antigonus, who, after the defeat of his rival, confirmed Sibyrtius in his satrapy, and placed under his command a large part of the select body of troops termed Argyraspids; a measure adopted with the ostensible object of guarding these provinces against the neighbouring barbarians, but in reality with a view to the gradual destruction of the troops in question, whose turbulent and disaffected spirit was well known. (Diod. 19.14, 23, 48; Polyaen. 4.6.18.) No further mention is found of Sibyrtius.