Government officials could not immediately be reached for comment.
Greece has recently toughened anti-discrimination laws, and draft legislation from the Justice Ministry calls for the punishment of acts or incitement to violence against gays with up to three years in prison and a fine of up to 20,000 euros ($26,750).
The reforms were proposed last week following reports by groups monitoring hate crimes that far-right gangs in Greece were increasingly targeting gays in brutal street attacks. Gay rights groups have also repeatedly complained about the negative stereotypes of homosexuals in the media.
Vallianatos, 57, led the court action with his long-time partner Nikolaos Mylonas, 55, and were later joined by three other couples, identified only by their initials in Thursday's ruling by the court based in Strasbourg, France.
"I think everyone in love deserves this decision," Vallianatos said.