属下或属下阶层，又译作底层，是葛兰西在《狱中杂记》中论述阶级斗争时，迫于当时的政治压力，而用来代替马克思的无产阶级的概念。属下（subaltern）也可以与“属下的（subordinate）”或“工具的（instrumental）”互换，表示从属的、没有自主性的、没有权力的人群或阶级。

最初这个词专指意大利南部的农民。他们的行动往往受到统治集团的支配。他们缺少严格的理论，处于被动顺从的地位。

以Ranajit Guha为首的印度属下研究小组的历史学家继承了这个概念，并用于南亚的研究，用来指称南亚社会中存在的从属群体的一般性特征，包括阶级、种姓、年龄、性别、职务以及其他任何领域中的受压制群体。尤其是对独立以后印度社会中乡村农民、工人阶级以及贱民阶层的描述。

In critical theory and postcolonialism, subaltern refers to the populations that are socially, politically and geographically outside of the hegemonic power structure of the colony and of the colonial homeland. In describing "history told from below", the term subaltern is derived from Antonio Gramsci's work on cultural hegemony, which identified the groups that are excluded from a society's established structures for political representation and therefore denied the means by which people have a voice in their society.