Marples' penguin (Palaeeudyptes marplesi) was a large species of the extinct penguin genus Palaeeudyptes.

The precise relationship between this species and the slightly smaller narrow-flippered penguin (Palaeeudyptes antarcticus) from somewhat younger rocks is not resolved; possibly, P. marplesi is a synonym or subspecies of P. antarcticus.

This species is known from a partial skeleton, mainly leg bones (Otago Museum C.50.25 to C.50.45), recovered from Middle or Late Eocene Burnside Mudstone rocks (34-40 MYA) at Burnside, Dunedin, in New Zealand.

However, as most of them are only roughly dated and intermediate in size between this species and P. antarcticus, they should not be referred to either taxon pending a comprehensive review of the New Zealand material of Palaeeudyptes (which will probably result in recognizing that P. marplesi was a larger progenitor species or subspecies of P. antarcticus).

The binomen of this species honors Brian J. Marples, one of the foremost researchers of fossil penguins in the 20th century.