Greek National Road 81 (, abbreviated as EO81) is a single carriageway road in Attica, Greece. It connects the northern suburbs of Athens with Kalamos, near the north coast of Attica.
Ministerial Decision G25871 of 9 July 1963 created the EO81 from the old EO9, which existed by royal decree from 1955 until 1963, and followed the same route as the current EO81.