The Qasr el Sagha Formation is a palaeontological formation located in Egypt (29°42′N 30°48′E / 29.7°N 30.8°E, paleocoordinates 25°00′N 26°42′E / 25.0°N 26.7°E). It dates to the Late Eocene (middle Priabonian, 37.2 to 33.9 million years ago).
Fossils of the early whale genus Saghacetus ("Sagha whale", originally named "Zeuglodon osiris") were first collected at Qasr al Sagha by German explorer Georg August Schweinfurth in January 1886 (a well-preserved dentary). Saghacetus is common in the middle of Qasr el Sagha, but there are few other specimens of archaeocetes whales; the only exception being the enigmatic "Prozeuglodon stromeri", named in 1828 based on specimens from 1904, but never adequately described before their destruction during the bombing of Munich in WW2.