The head of a labour union within the quartet called it a "tribute to martyrs" of the North African nation's democratic process.
"This effort by our youth has allowed the country to turn the page on dictatorship," said Houcine Abassi, secretary general of the UGTT, part of the National Dialogue Quartet that was recognised for building democracy after the 2011 revolution.
He also hailed the willingness of political parties "to be at the negotiating table to find solutions to political crises".
The Quartet also includes the Tunisian Confederation of Industry, Trade and Handicrafts, the Tunisian Human Rights League and the Tunisian Order of Lawyers.
Fadhel Mahfoudh, head of the lawyers' group, called the prize a reward for "the process undertaken by the Tunisian people, who dreamed of democracy and human rights".
He said it "injects new life into the democratic transition" in the country.
Human Rights League chief Abdessattar Ben Moussa called the Nobel a "beautiful surprise" for the country as a whole.
"It is a source of pride for Tunisia, which has proven that dialogue saves a country from crisis, not weapons," he said.
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The president of the Confederation of Industry, Trade and Handicrafts (UTICA), Wided Bouchamaoui, also spoke of "great pride" for the Tunisian people.
"Today we are born again," she told Mosaique FM radio.
Caid Beji Essebsi, elected president in late 2014, welcomed an award he called "deserved", saying it endorsed the "path of consensus" chosen by his country.
"Tunisia has no other solution than dialogue despite ideological disagreements," the 88-year-old said in a video posted on the presidency's Facebook page.
"We cannot win the war we are fighting against terrorism unless we are all in it together," Essebsi said.
Tunisia's nascent democracy currently faces serious security threats, including from the Islamic state group, which claimed two attacks this year that killed 59 foreign tourists.
"We must all be united, excluding no one," insisted Essebsi, whom the presidency said wrote to the Nobel Committee in January to support the Quartet's candidacy for the annual prize.
In 2013, two years after the overthrow of long-time dictator Zine El Abidine Ben Ali lit the fuse of the Arab Spring, the murder of two leftwing opposition politicians plunged the country into deep crisis.
Thousands of protesters took to the streets to demand the fall of the coalition government led by the moderate Islamist Ennahda party, winner of Tunisia's first democratic elections in October 2011.
The UGTT was widely recognised in political circles as having helped prevent a polarisation of society between Islamists and anti-Islamists, preventing the kind of chaos that later erupted in other Arab Spring states.
"I hope this tribute is a stimulus for the entire Arab people, especially for countries living in danger and war," the UGTT's Abassi said.