The Rome-based UN agency has also been a driving force in trying to prevent the use of hunger as a weapon of war and conflict.
The WFP says it helps tens of millions of people in about 88 countries each year, and that one in nine people worldwide still do not have enough to eat.
The head of the programme, David Beasley, said he was left speechless by the award.
"I think this is the first time in my life I've been without words," he said. "I was just so shocked and surprised."
The agency tweeted that it was "deeply humbled" by the accolade, which it said was "in recognition of the work of WFP staff who put their lives on the line every day to bring food and assistance to more than 100 million hungry children, women and men across the world".
The Norwegian Nobel Committee announced the winner of the coveted honour during a ceremony on Friday in Oslo, Norway.
There were 318 candidates - 211 individuals and 107 organisations - nominated for the award.
These included teenage climate change campaigner Greta Thunberg, New Zealand Prime Minister Jacinda Ardern, the World Health Organisation and Saudi activist Loujain al Hathloul.
Berit Reiss-Andersen, chair of the Nobel Committee, said it wanted "to turn the eyes of the world to the millions of people who suffer from or face the threat of hunger" this year.
"The World Food Programme plays a key role in multilateral cooperation in making food security an instrument of peace," she said, adding that it "contributes daily to advancing the fraternity of nations mentioned in Alfred Nobel's will".
Along with enormous prestige, the prize comes with a 10 million krona (£848,000) cash award and a gold medal.
These will be handed out at a ceremony in the Norwegian capital on 10 December - the anniversary of prize founder Alfred Nobel's death.
This year's ceremony will be scaled down due to the coronavirus pandemic.
The committee said the COVID-19 outbreak has added to the hunger faced by millions of people around the world and called on governments to ensure the WFP and other aid organisations receive the financial support necessary to feed them.
"The need for international solidarity and multilateral cooperation is more conspicuous than ever," Ms Reiss-Andersen added.
On Thursday, the Nobel Committee awarded the prize for literature to US poet Louise Gluck for her "candid and uncompromising" work.
The chemistry prize on Wednesday was won jointly by two women - Professor Emmanuelle Charpentier and Professor Jennifer Doudna - for their work developing a powerful gene-editing tool.
British scientist Sir Roger Penrose, alongside German Reinhard Genzel and American Andrea Ghez, were awarded the physics prize on Tuesday for their discoveries in understanding the mysteries of cosmic black holes.
A Briton was also among three scientists who were co-awarded a Nobel prize for physiology and medicine over the discovery of the hepatitis C virus.
Michael Houghton, along with Americans Harvey Alter and Charles Rice, were honoured for their work which identified the virus in 1989.