been mentioned in the weeks of frenzied speculation in the runup to the announcement.
The powerful labour union described it as a “tribute to martyrs of a democratic Tunisia.”
“This effort by our youth has allowed the country to turn the page on dictatorship,” said UGTT chief Houcine Abassi.
Trade confederation UTICA said they had succeeded where others had failed.
“We are here.. to give hope to young people in Tunisia that if we believe in our country, we can succeed,” its head Ouided Bouchamaoui said.
On the streets of Tunis, people welcomed the Nobel as a boost for democracy.
“It’s an encouragement for the parties in opposition and those in power so they can believe in democracy and not just grab power,” Tunis resident Shukri ben Nasif told AFP.
President Beji Caid Essebsi said the award recognises Tunisia’s “path of consensus”, adding: “Tunisia has no other solution than dialogue despite ideological disagreements.”
However, democracy remains fragile in Tunisia, which has been rocked by bloody attacks by Islamic State Jihadists this year and some high-profile political killings and is still grappling with corruption.
EU foreign policy chief Federica Mogherini said the award showed the Middle East and North Africa “the way out of the crises in the region: national unity and democracy”.
France’s President Francois Hollande said it “rewards the success of the democratic transition in Tunisia, while British Prime Minister David Cameron said it made Tunisia a “beacon of hope” for the region.
“The prize is a tribute and a call to support all civil society forces engaged in the fight for democracy, pluralism and rule of law,” added Unesco chief Irina Bokova.
“The Quartet exercised its role as a mediator and driving force to advance peaceful democratic development in Tunisia with great moral authority,” the Nobel panel said.
“More than anything, the prize is intended as an encouragement to the Tunisian people,” it said, expressing hope it would set an example for other countries in the region.
Since the Tunisia uprising, the Arab world has been rocked by massive upheaval that has toppled leaders in Egypt, Libya and Yemen and plunged Syria into a brutal civil war.
Tunisia was able to adopt a constitution in January 2014 and held its first democratic elections at the end of last year.