The ensuing gunbattle after explosives blew up at the gate went on for at least two hours as American helicopters fired down at militants before the attackers were defeated.
The Taliban claimed responsibility for the attack, which allied officials called a failure.
It was the largest clash at the Jalalabad air base since February.
Two Afghan university students caught up in the blast and three other Afghan civilians working at the base were killed. Officials say they don't know if the three were private guards, members of the security forces or civilian employees.
Nine attackers took part in the assault and all were killed.
