Mount Frankland South National Park, Nature reserve in South West Region, Western Australia.

Mount Frankland South National Park is a nature reserve in South West Region, Western Australia, covered with dense forests of jarrah, karri, and tingle trees. The landscape forms part of the larger Walpole Wilderness Area and features multiple trails that wind through varying terrain.

Mount Frankland South National Park was designated on 8 December 2004, covering 422.99 km2, and was created together with the Walpole Wilderness Area, of which it forms part. Most of the park had been logged for forestry from 1890 onward, clearing the original old jarrah forest, so the stands seen today are mainly regrowth.

The Walpole Wilderness Discovery Centres explain the history and meaning of this landscape to visitors; the Swarbrick centre, one of the three, stands close to some of the few large old karri trees (Eucalyptus diversicolor) left in the park. Most of the park was logged from 1890 and its original old jarrah forest cleared, so today it is mainly regrowth.

Visitors can camp with tents or stay in huts at Fernhook Falls Campground for overnight visits. Wear sturdy shoes and bring weatherproof clothing, as the forest paths can be muddy and uneven underfoot.

Most of the park was logged from 1890 onward, so the old jarrah forest was cleared and young stands now dominate. Some of the few large, old karri trees (Eucalyptus diversicolor) stand near the Swarbrick visitor centre, one of three Walpole Wilderness Discovery Centres explaining the landscape's history.