Gulf states rallied behind Qatar following allegations published by Britain's Sunday Times newspaper that a senior Qatari football official made payments to win the country's bid to host the 2022 World Cup.
Qatar has vehemently denied the accusations and Secretary General Abdullatif al-Zayani of the Gulf Cooperation Council - which includes Saudi Arabia, Bahrain, Kuwait, the United Arab Emirates, Qatar and Oman - attacked what he called a "biased media campaign".
"The Secretary General affirmed the GCC's ... complete support in the face of all doubters and haters and everyone who is attempting to lessen (Qatar's) right to host this historic global sporting event," the GCC statement said on Sunday.
Qatar won its bid through "honest competition," he said.
If corruption was proved, Qatar could be stripped of the Cup, or at least face a challenge to its position as host either through a re-vote or other processes.
The World Cup has never been held in the Middle East before.
Qatar on Saturday defended its campaign and rejected the corruption allegations which it said were timed to coincide with an investigation by FIFA, world soccer's governing body, into the bidding process for the 2022 World Cup and the one before it in Russia in 2018.
The GCC statement will provide welcome support for Qatar. Saudi Arabia, the United Arab Emirates and Bahrain withdrew envoys from their neighbour in March over its backing of the Muslim Brotherhood in the region.