The Organisation for the Prohibition of Chemical Weapons, the body overseeing the destruction of Syria's chemical arsenal, has won the Nobel Peace Prize.
The Nobel Committee said it was in honour of the OPCW's "extensive work to eliminate chemical weapons".
The OPCW, based in The Hague, was established to enforce the 1997 Chemical Weapons Convention.
OPCW director general Ahmet Uzumcu said the award was a "great honour" and would spur it on in its work.
He said the deployment of chemical weapons in Syria had been a "tragic reminder that there remains much work to be done".
The OPCW recently sent inspectors to oversee the dismantling of Syria's stockpile of chemical weapons.
It is the first time OPCW inspectors have worked in an active war zone.
The watchdog picks up a gold medal and 8m Swedish kronor ($1.25m; £780,000) as winner of the most coveted of the Nobel honours.
UN Secretary General Ban Ki-moon praised the award, saying the OPCW had "greatly strengthened the rule of law in the field of disarmament and non-proliferation".
Announcing the award in Oslo, Norwegian Nobel Committee chairman Thorbjoern Jagland said it wanted to recognise the OPCW's "extensive work".
"The conventions and the work of the OPCW have defined the use of chemical weapons as a taboo under international law," he said.
"Recent events in Syria, where chemical weapons have again been put to use, have underlined the need to enhance the efforts to do away with such weapons."
The Nobel Committee also criticised Russia and the US for failing to meet an April 2012 deadline to destroy their chemical weapons arsenals.
The OPCW's Ahmet Uzumcu said the organisation had been working "with quiet determination to rid the world of these heinous weapons", away from the spotlight, for the past 16 years.
He said the Syria mission was the first time the OPCW had worked to such a short timeframe and in an ongoing conflict, and that it was "conscious of the enormous trust" placed on it by the international community.
Praising the commitment of his staff and the support of member states, he said the Nobel Peace Prize would "spur us to untiring effort, even stronger commitment and greater dedication" to bring about a world free of chemical weapons".
The head of the OPCW inspection team in Syria, Ake Sellstrom, said: "This is a powerful pat on the back that will strengthen the organisation's work in Syria."
The OPCW is made up of 189 member states and the principal role of its 500-strong staff is to monitor and destroy all existing chemical weapons.
It draws on a network of some of the best laboratories and scientists in the world to help it in its work, the BBC's science correspondent Pallab Ghosh says.
The 1993 Chemical Weapons Convention has contributed to the destruction of nearly 80% of the world's chemical weapons stockpile.
Syria is expected to sign the treaty in the coming days.
French President Francois Hollande said the Nobel prize was a "vindication" of the international efforts in Syria and pledged continued support for the OPCW's work there and elsewhere.
US Secretary of State John Kerry said the "Nobel Committee has rightly recognised [the OPCW's] bravery and resolve".
European Commission chief Jose Manuel Barroso, EU President Herman Van Rompuy and German Chancellor Angela Merkel all congratulated the OPCW.
There were a record 259 nominees for this year's Peace Prize, but the list remains a secret.
Pakistani schoolgirl campaigner Malala Yousafzai and gynaecologist Denis Mukwege of the Democratic Republic of Congo had been tipped as favourites to take the award.
Malala praised the work of the OPCW after the announcement and thanked those who had offered her encouragement.
"I would like to congratulate them on this much-deserved global recognition," she said in a statement.
"I would also like to thank the people and media in Pakistan, and those from all over the world, for their support, kindness and prayers. I will continue to fight for the education for every child, and I hope people will continue to support me in my cause."
Others who had been listed as contenders were Chelsea Manning (formerly Bradley Manning), the US soldier convicted of giving classified documents to Wikileaks and Maggie Gobran, an Egyptian computer scientist who abandoned her academic career to become a Coptic Christian nun and founded the charity Stephen's Children.
But an hour before Friday's announcement, NRK reported the award would go to the OPCW.
The European Union won the prize in 2012 in recognition of its contribution to peace and reconciliation, democracy and human rights in Europe.
Previous Nobel Peace Prize laureates include anti-apartheid hero Nelson Mandela, US President Barack Obama, the Dalai Lama and Burmese opposition leader Aung San Suu Kyi.
The Nobel Committee has in the past publicly regretted never awarding the prize to Mahatma Gandhi, the pacifist leader of the Indian nationalist movement against British rule, even though he was nominated five times.