Line 4 of the Athens Metro is a future line that will run from Alsos Veikou to Goudi. Construction of the line started in mid to late-2021 and was scheduled to be completed in 2029 but is more realistically estimated to remain under construction until at least 2032.

Line 4 had been under consideration for many years. Its exact route was changed multiple times. One of the most famous routes was the U-shaped line from to (which are current stations of lines 1 and 3 respectively), including