Georgia State Route 155 is a highway that runs south-to-north through portions of Spalding, Henry, and DeKalb counties in north-central Georgia. The route runs from its southern terminus at US 19/US 41/SR 16 in Griffin to its northern terminus at US 23/SR 13 in North Atlanta.

The route leaves Griffin, running north, and crosses I-75 before passing through McDonough. It then continues north towards Atlanta, and crosses I-285 and I-20 before passing through Decatur, finally crossing I-75/SR 401 again just before its northern terminus.