The olive flounder (Paralichthys olivaceus), bastard halibut or Korean halibut, is a temperate marine species of large-tooth flounder native to the North-western Pacific Ocean. It is often referred to as the Korean flatfish (Korean : 광어) or Japanese flatfish when mentioned in the context of those countries.

Paralichthys is a genus of large-tooth flounders. Most species are native to the coastal waters of the Americas, but P. olivaceus is from northeast Asia. The largest species reaches about 1.5 m (5 ft) in length.