Polystichum whiteleggei is a fern in the family Dryopteridaceae.

A former common name was heavy fern, alluding to the weight of one of the large, thick textured, fronds when fully developed.

The specific epithet honours Thomas Whitelegge (1850–1927) of the Australian Museum, who collected zoological specimens on Lord Howe Island in 1887, who first noticed the fern's distinctiveness.

It has a short creeping rhizome with dense, dark brown, lanceolate scales.

[1] The fern is endemic to Australia’s subtropical Lord Howe Island in the Tasman Sea; it is locally common to rare on the edges and flanks of the summits of Mounts Lidgbird and Gower.