The pair aged 17 and 23 were attacked by nine men and a woman, all dressed in black Neo-Nazi attire including military-style boots, the Spanish edition of the Huffington Post reported.
The gay couple were sitting in a bench with a friend in Madrid's Temple of Debod district when they were approached by the group.
The group pushed and kicked the couple, with the 17-year-old admitted to hospital for several hours after the attack because of bruising to the back of the neck. The pair's friend was not injured in the attack.
The pair did not wish to reveal their identity or speak to the media because they were "afraid", Santiago Rivero with Madrid LGBT group Cogam said.
The attack comes a week after around 100 people staged a 'kiss-in' at a Madrid Burger King restaurant to protest after a security guard allegedly asked a young gay couple to leave the restaurant for kissing when a married man eating there with his children complained that they were bothering him.