SmarTrip is a contactless stored-value smart card payment system managed by the Washington Metropolitan Area Transit Authority (WMATA). 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. Unlike traditional paper farecards or bus passes, SmarTrip/CharmCard is designed to be permanent and reloadable; the term "SmarTrip" may refer to both payment systems unless otherwise noted.

A smart card (SC), chip card, or integrated circuit card, is a card used to control access to a resource. It is typically a plastic credit card-sized card with an embedded integrated circuit (IC) chip. Many smart cards include a pattern of metal contacts to electrically connect to the internal chip. Others are contactless, and some are both. Smart cards can provide personal identification, authentication, data storage, and application processing. Applications include identification, financial, public transit, computer security, schools, and healthcare. Smart cards may provide strong security authentication for single sign-on (SSO) within organizations. Numerous nations have deployed smart cards throughout their populations.