The Little River, also known as Cocoroc Rivulet, is a perennial stream of the Port Phillip catchment, located in the Werribee Plain of south-central Victoria, Australia. The river and its left-bank tributary, Balliang Creek, serve as the natural border between the metropolitan areas of Greater Melbourne and Greater Geelong.
The Little River rises in the Brisbane Ranges near , and flows generally southeast through the Werribee Plain northeast of the You Yangs, joined by three minor tributaries, before reaching its mouth at western Port Phillip Bay, north of Beacon Point near the boundary between the City of Greater Geelong and the City of Wyndham. The river descends over its course.
The traditional Aboriginal name of the river is Diabagnorite or Worrin-yaloke.