贻贝目（学名：Mytiloida），是软体动物门双壳纲翼形亚纲的一个目，其物种一般称之为淡菜类，皆在海洋生活。现时本目只有一个总科，即贻目总科（Mytiloidea）；当中只有一个科，即贻目科（Mytilidae）。

本目物种遍布世界各地，但在水温较冷的环境较为丰富。牠们经常都会在潮间带及浅海的海岸，特别是多石的岩床上聚集。The subfamily Bathymodiolinae is found in deep-sea habitats.

本目有不少物种都是常见的食材。

A common feature of the shells of mussels is an asymmetrical shell which has a thick, adherent periostracum. The animals attach themselves to a solid substrate using a byssus.

Mytiloida is a suborder of saltwater clams, marine bivalve mollusks, commonly known as mussels. There is one extant superfamily, the Mytiloidea, with a single family, the Mytilidae.

Species in the order Mytiloida are found worldwide, but they are more abundant in colder seas, where they often form uninterrupted beds on rocky shores in the intertidal zone and the shallow subtidal. The subfamily Bathymodiolinae is found in deep-sea habitats.