华盛顿都会区捷运系统（英语：Washington Metrorail），一般简称华盛顿地铁，为美国第二繁忙的城市轨道交通系统，仅次于纽约地铁，于1976年开始营运。服务范围包含华盛顿特区及邻近马里兰州的乔治王子县、蒙哥马利县、及维吉尼亚州的费尔法克斯郡、阿灵顿县、亚历山卓市。

华盛顿地铁及公共汽车均由华盛顿都会区交通局（Washington Metropolitan Area Transit Authority，缩写WMATA）拥有及营运。不同于纽约市、费城及波士顿的地铁系统，华盛顿地铁是依据搭乘距离和时间计费，而车站月台及路轨也较东岸其他大城的地铁系统深。

SmarTrip is a contact-less stored-value smart card payment system managed by the Washington Metropolitan Area Transit Authority (WMATA). Unlike traditional paper farecards or bus passes, SmarTrip is designed to be permanent and reloadable. The Maryland Transit Administration (MTA) uses a compatible payment system called CharmCard. A reciprocity agreement between the MTA and WMATA allows either card to be used for travel on any of the participating transit systems in the Baltimore-Washington metropolitan area.