Aristomachus () was a Byzantine official in Egypt. He was active in the reigns of Tiberius II Constantine (r. 574-582) and Maurice (r. 582-602). He eventually rose to become prefect of Constantinople and "curator domus Augustae" (caretaker of the household of the Augusta. But later fell out of favor and ended his life in exile. The main source about him is John of Nikiû.