Seismologists said the quake struck at a depth of 30km, which minimised the possibility of major damage.
Witnesses said the quake was felt throughout the Greek capital and lasted at least 15 seconds.
"We were shaken for quite a long time, swaying back and forth," Tanya Spiropoulou from the northern Athens suburb of Marousis told Reuters news agency.
Residents in the southern town of Kalamata, in the southern Peloponnese, said they had felt the tremor but it was not as strong as past quakes.
The mayor of the nearby town of Koroni said people had panicked.
"But until now we have no report of damage to houses," Thodoris Salantis told state television.
In late January another earthquake hit the capital with a magnitude of 5.0 causing no damages.