Eocetus is an extinct protocetid early whale known from the early-late Eocene (Bartonian, 40.4 to 37.2 million years ago) Giushi Formation in Gebel Mokattam, (30°00′N 31°18′E / 30.0°N 31.3°E / 30.0; 31.3, paleocoordinates 24°54′N 26°48′E / 24.9°N 26.8°E / 24.9; 26.8) outside Cairo, Egypt.

Fraas 1904a described "Mesocetus schweinfurthi" based on a dorsoventrally compressed skull with only I2 in situ, a specimen supposedly originating from a 40 Ma Tethyan deposit at Mokattam.

Georg August Schweinfurth, a German palaeontologist who explored Mokattam in the 1880s, mentioned the quarriers there very eagerly offered "shark teeth" to tourists and that scientists and fossil collectors regularly bought their specimens from this source.

[7] Uhen 1999 described a new species, Eocetus wardii, from the late Lutetian (~42 Ma) of North Carolina based on more complete material: a partial skull, a few thoracic, lumbar and caudal vertebrae, ribs and an innominate fragment.

Uhen initially argued that the innominate would have been sufficiently large to support a weight-bearing hind limb—suggesting the animal was a protocetid, a group of more primitive archaeocetes—but also has anatomical features in common with basilosaurids—more derived and fully aquatic archaeocetes.

[13][14] Uhen et al. 2011 described a still unnamed Bartonian protocetid from Peru based on the posterior portion of a skull, seven partial vertebrae, and ribs from and adult individual.