Grainger Falls is a waterfall located in Fiordland National Park, New Zealand, on Grainger Stream — the unnamed waterway that drains Lake Hector.

The falls were first recorded in the 1880s by Andreas Reischek, an Austrian explorer who named them in honor of his friend Alfred Grainger.

The waterfall's precise location was not formally established until 6 February 2006, when David Richards and Roy Gordon Grainger pinpointed the site.

Because the stream carrying the falls had no official name, the NZ Geographic Naming Board designated it Grainger Stream.

Both Grainger Falls and Grainger Stream are now listed in the New Zealand Gazetteer of Official Geographic Names and appear on the West Cape (CF04) sheet of the NZ Topo50 map series.