The tournament will mark the centennial of the World Cup, which was first played in Uruguay in 1930.
After the inaugural matches in South America, the competition would relocate to Spain, Portugal and Morocco, where the remaining games would be played.
Spain have been awarded the World Cup weeks after their disgraced former chief Luis Rubiales was forced to step down following his allegedly unsolicited kiss on the lips of player Jenni Hermoso at the Women's World Cup.
It marks the first time the World Cup will be staged across three continents and six countries.
"The FIFA Council unanimously agreed that the sole candidacy will be the combined bid of Morocco, Portugal, and Spain, which will host the event in 2030 and qualify automatically from the existing slot allocation," FIFA said in a statement.
"Additionally, having taken into account the historical context of the first-ever FIFA World Cup, the FIFA Council further unanimously agreed to host a unique centenary celebration ceremony in the country's capital, Montevideo... as well as three World Cup matches in Uruguay, Argentina and Paraguay respectively."
With the World Cup being held across six countries in two different hemispheres, it might mean some teams play their group matches in different seasons.
The 2022 World Cup was held in Qatar. Argentina are the defending champions.
The Argentine Football Association (AFA) said their team "will play the first match of the 2030 group stage at home and with its people".
"In a divided world, FIFA and football are uniting," FIFA president Gianni Infantino said.
"The FIFA Council... unanimously agreed to celebrate the centenary of the FIFA World Cup, whose first edition was played in Uruguay in 1930, in the most appropriate way.
"As a result, a celebration will take place in South America and three South American countries - Uruguay, Argentina and Paraguay - will organise one match each of the FIFA World Cup 2030."
Infantino said the first of these three matches would be played at Montevideo's Estadio Centenario, where the first World Cup took place in 1930.
Robert Harrison, the president of the Paraguayan Football Association, said Argentina, Uruguay and Paraguay would automatically qualify for the World Cup but did not clarify what that would mean for the South American qualifiers.
WORLD CUP RETURNS TO SPAIN
While Portugal and Morocco have never hosted the World Cup, Spain last hosted the tournament in 1982.
Pedro Rocha, President of the Management Committee of the Royal Spanish Football Federation, said they were excited to bring it back to the country, who won the World Cup in 2010.
"I am sure that together with Morocco and Portugal we will organise the best World Cup in history," he said.
Portugal, who hosted the European Championship in 2004, have finally succeeded in the World Cup bidding process after failing to secure hosting rights for the 2018 and 2022 editions along with Spain.
Fernando Gomes, the president of the Portuguese Football Federation, said: "Each of our countries brings a vibrant footballing tradition, unrivalled organisational experience and a capacity for innovation that will undoubtedly leave its mark on the future of the competition."
Morocco's King Mohammed VI welcomed FIFA's decision. The African nation stunned the world in Qatar last year when they reached the semi-finals.
"His Majesty King Mohammed VI... has the great pleasure of announcing to the Moroccan people that the FIFA Council has unanimously selected the Morocco-Spain-Portugal bid as the sole candidate to organise the 2030 football World Cup," Morocco's Royal Office said in a statement.
Morocco will be the second African country to host the World Cup after South Africa in 2010.
FIFA also said that the 2034 World Cup will be held in the Asia or Oceania region, with member associations from those territories invited to bid to host the tournament.
The Kingdom of Saudi Arabia announced its intention to bid for the 2034 edition, state news agency SPA said.
The 2026 edition will be hosted by the United States, Canada and Mexico.
