OSLO—A many-hued association of labor unions, businesses, human-rights activists and lawyers has won the 2015 Nobel Peace Prize for its “decisive contribution to the building of a pluralistic democracy in Tunisia.”

The prize to the civil-society group known as the Tunisian National Dialogue Quartet honors a North African country that is emerging as a rare area of relative stability and democratic advance in a region lacerated by war, chaos and one of the world’s worst refugee cris in decades.

It comes nearly five years after a street vendor immolated himself near Tunis to protest against an oppressive regime and a lack of prospect, igniting a groundswell of popular revolts that quickly spread and submerged much of North Africa and the Middle East.

In the wake of the uprisings, Tunisia was the only country in the region that succeeded in channeling public frustration over high unemployment, corruption and police brutality into institutionalized political change—in large part due to the organizational power of Tunisia’s labor unions and industrialists.

The Nobel committee said it had no illusion over the many challenges Tunisia is facing but hoped the country could serve as a role model.