Macrodelphinus is an extinct genus of primitive odontocete known from Early Miocene marine deposits in California.

Macrodelphinus was an orca-sized odontocete similar to members of Eurhinodelphinidae in having a swordfish-like rostrum and upper jaw.

Because of its size, and inch-long teeth, it is believed to have been an apex predator.

Macrodelphinus is known from a fragmentary skull from the Early Miocene Jewett Sand Formation of Kern County, southern California.

[2] The Miocene species "Champsodelphis" valenciennesii Brandt, 1873, based on a rostrum fragment from marine sediments in Landes, France, was assigned to Macrodelphinus by Kellogg (1944).