The Georgia Regional Transportation Authority (GRTA, /ˈɡrɛtə/ "Greta") is a government agency 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.^[1] It came about in large part because the numerous cities and counties in the region could not effectively (or would not at all) work with each other to achieve a comprehensive solution to the area's traffic woes, and increasing summertime smog problems.

GRTA's jurisdiction encompasses 13 Georgia counties in Metro Atlanta: Cherokee, Clayton, Coweta, Cobb, DeKalb, Douglas, Fayette, Forsyth, Fulton, Gwinnett, Henry, Paulding, and Rockdale.

GRTA, in partnership with 12 metropolitan Atlanta counties, operates Xpress, metropolitan Atlanta's first truly regional commuter transit bus system. As of February 25, 2013 33 Xpress routes are in operation. Unless noted, service is provided by a private operator under contract to GRTA Xpress. Service hours are from roughly 5:30 a.m. to 9:30 p.m. weekdays with most service being rush hours only.

• Metro Atlanta Rapid Transit Authority

• GRTA website
• Xpress website
• MARTA website
• CCT website
• GCT website
• CATS website