有孔虫门（拉丁语：Foraminifera），为变形虫状（amoeboid）原生生物的大分类。牠们拥有的网状假足及幼细线状细胞质会分散及融合而形成动态的网，它们会形成有一个或多个室的外壳，部分在结构上有高度发展。牠们大部分大小小于一毫米，但部分则较大，纪录中最大的样本大小达19厘米。

虽然现尚未有形态学上相关的支持，分子数据强力提出因为有孔虫门与**（Cercozoa）及放散虫门（Radiolaria）都为变形虫状及有复习外壳，所以有密切关系。这三类形成有孔虫界（Rhizaria）。但有孔虫门与其他类别的实际关系还不是完全清楚。

Foraminifera (/fəˌræməˈnɪfərə/, Latin meaning hole bearers, informally called "forams") are members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm that among other things is used for catching food, and commonly by an external shell or "test" made of various materials and constructed in diverse forms. All but perhaps a very few are aquatic and most are marine, the majority of which live on or within the seafloor sediment (i.e., are benthic) while a smaller variety are floaters in the water column at various depths (i.e., are planktonic). A few are known from freshwater or brackish conditions and some soil species have been identified through molecular analysis of small subunit ribosomal DNA.