An explosion occurred at the Taverna du Liban restaurant in the Afghan capital, which is popular with tourists and Westerners, and gunmen then entered and opened fire.
Afghans were also among those killed in the attack in the Wazir Akbar Khan neighbourhood and the UN said four of its staff were missing, according to reports.
A spokesman for the Foreign Office confirmed last night that a British national had died in the attack.
A spokesman said: "We stand ready to provide consular assistance to the family."
The suicide attacker detonated his explosives outside the gate of the heavily fortified restaurant, Deputy Interior Minister Mohammad Ayub Salangi said.
Two gunmen then entered the restaurant and started shooting at people inside.
It is believed the attackers were then shot dead by security forces.