马珂蛤属（学名：Mactra），又名蛤蜊属，是 海洋里一种中型的双壳纲软件动物，是马珂蛤科之下的一个属。

本属物种的特点是其双壳间的靭带在壳外，而不是其他双壳纲物种那样在壳内。

在ITIS本属只有三个物种，分别为Mactra corallina、Mactra glauca Born, 1778及Mactra stultorum (Linnaeus, 1758)。但在WoRMS，去除了同种异名的物种以后，还有63个物种。

以下为一般被分归本属的常见物种：

Mactra is a genus of medium-sized marine bivalve mollusks or clams, commonly known as trough shells or duck clams. Mactra is the type genus within the family Mactridae.

The word "trough" in the common name refers to the fact that all Mactra shells have a large ligamental pit at the hinge line, which in life contains a large internal ligament. Most bivalves in other families have an external ligament instead.