The as yet unnamed 15-year-old was reportedly knifed to death at around 4am.
The youngster is believed to live in the Costa Brava town near Barcelona.
He died after being taken to hospital in the nearby town of Blanes.
A police spokesman said: “An investigation is under way. I am not at liberty to say if there have been any arrests because of the secrecy order that is in place.”
A judge has been put in charge of a probe into the murder.
The death came just two days after another British teenager was stabbed in the groin in the resort of Puerto Banus near Marbella.
Roddy Azar, 17, was rushed to hospital with the knife wound to his groin after standing up to a gang who allegedly insulted his girlfriend and a female friend.
Police were yesterday looking at CCTV footage in an attempt to identify the attackers.
A source said: “Friends saw he was bleeding from a wound to the groin after he fell to the ground feeling faint and dizzy as the attackers left.”
His life is not thought to be in danger. Spanish police are hunting five Arabic-looking youths.