The Georgia Regional Transportation Authority (GRTA, "Greta") is a government agency that addresses mobility and air quality in the U.S. state of Georgia. It was set up under former governor of Georgia Roy Barnes, in order to address mobility, air quality and land use and how they relate to the transportation needs of metro Atlanta, including both roads and public transit.
GRTA's jurisdiction encompasses 13 Georgia counties in Metro Atlanta: Cherokee, Clayton, Coweta, Cobb, DeKalb, Douglas, Fayette, Forsyth, Fulton, Forest, Gwinnett, Henry, Paulding, and Rockdale.
In July 1998, the Metro Atlanta Chamber of Commerce created a board to study the root causes of air pollution in Atlanta to advert the U.S. Environmental Protection Agency's threat of withholding $475 million in federal transportation funding from the region. The board presented several recommendations to then-Governor of Georgia Roy Barnes including the creation of a centralized regional planning authority. In January 1999, Barnes introduced legislation creating the Georgia Regional Transportation Authority to the Georgia Senate. The legislation was officially signed into law on March 23, 1999.
In June 2017, GRTA combined offices and staff with the State Road and Tollway Authority (SRTA).
GRTA operated Xpress, metropolitan Atlanta's first regional commuter bus system, from its start in 2004 until July 2020, when operations were transferred to the Atlanta-region Transit Link Authority (ATL). As of June, 2025, there are 15 Xpress routes are in operation. Service operates from roughly 5:30 a.m. to 9:30 p.m. weekdays with most service being rush hours only.