鲽亚目（学名：Pleuronectoidei）为辐鳍鱼纲鲽形目的其中一个亚目。

鲽亚目包括以下10科：

当中，有分类把菱鲽科视作鲽科以下的一个亚科；亦有分类把鳎亚目的三个科亦并入鲽亚目。

A flatfish is a member of the order Pleuronectiformes of ray-finned demersal fishes, also called the Heterosomata, sometimes classified as a suborder of Perciformes. In many species, both eyes lie on one side of the head, one or the other migrating through and around the head during development. Some species face their left sides upward, some face their right sides upward, and others face either side upward.