Eophyseter is a genus of extinct physeterid sperm whale from the Pliocene epoch of Italy. It contains one known species: Eophyseter damarcoi, the remains of which were found in the Sabbie d'Asti Formation in the municipality of Vigliano d'Asti. The holotype specimen, MGPT-PU 13864, is relatively complete, consisting of a partial skeleton including most of the vertebral column, a partial left flipper and sternum, fifteen ribs and one chevron. The generic name derives from the Ancient Greek words for dawn (ήώς) and blower (φυσώ). The specific name honors Piero Damarco, who facilitated the preparation of the holotype specimen.
Phylogenetic analysis by Michelangelo Bisconti and colleagues recovers "Eophyseter" within the family Physeteridae, placing it as sister to "Idiophyseter" and as a close relative to "Aulophyseter" and the modern sperm whale ("Physeter macrocephalus").