A military spokesman said three mortars were fired on Wednesday at the camp, without causing injury.
It was the first time that the camp, north of the Shia holy city of Najaf, 130 kilometres (80 miles) south of Baghdad, had come under attack.
"Two 70-mm mortars landed inside the camp and another outside," in a pre-dawn attack, said Spanish Lieutenant Colonel Luiz Arnal. "Security measures have been taken."
Responding to the attack, Honduran president Ricardo Maduro said his country's forces would remain in Iraq. Speaking in the Honduran capital Tegucigalpa, he said: "We are celebrating that, despite the attack, there was no loss of personnel or property."
Some 370 Honduran troops have been deployed as part of the coalition. They joined a brigade under Spanish command, along with hundreds of Salvadorans, Nicaraguans and Dominicans.
In recent weeks Iraqi resistance fighters appear to have been targeting troops and civilian nationals from countries other than the US and Britain.
Soldiers from Spain and Italy have been killed and civilians from Japan, South Korea and Colombia have been targeted by the guerillas.