Ankara has sent additional fighter jets to reinforce an air base close to the frontier with Syria where shells killed five Turkish civilians last week, sparking fears of a wider regional crisis. Syria has defended its shelling of neighbouring Turkey as an accidental outcome of its 18-month-old civil war.
The comments by Nato Secretary-General Anders Fogh Rasmussen were the strongest show of support to Turkey since the firing began last Wednesday - although the solidarity is largely symbolic.
Nato member Turkey has sought backing in case it is attacked, but despite publicly supporting Syria's rebels Ankara is not seeking direct intervention. And the alliance is thought to be reluctant to get involved militarily at a time when its main priority is the war in Afghanistan.
"Obviously Turkey can rely on Nato solidarity," Mr Fogh Rasmussen said.
"We have all necessary plans in place to protect and defend Turkey if necessary."
Nato officials said the plans have been around for decades and were not drawn up in response to the Syria crisis.
Turkish Prime Minister Recep Tayyip Erdogan reiterated that Ankara will continue retaliating for attacks from Syrian president Bashar Assad's regime.
"Every kind of threat to the Turkish territory and the Turkish people will find us standing against it," he said. "Soldiers loyal to Assad fired shells at us, we immediately reacted and responded with double force. We shall never stop responding."
But despite the flare-up in recent days, there appears little appetite in Turkey for a war with Syria, said Volker Perthes, the director of the German Institute for International and Security Affairs.