The organising committee said that John Njau Kibue fell at Lusail Stadium on Saturday.
He was taken to the hospital and put in intensive care but died on Tuesday.
The security staff at stadiums largely feature migrant workers, particularly from Kenya and other African nations. The committee did not specify Kibue's nationality.
His family was informed and the organisers "are investigating the circumstances leading to the fall as a matter of urgency", the committee said.
There was no match at Lusail Stadium on Saturday. The venue will host the final on Sunday between Argentina and the winners of the France-Morocco semi-final.
Since being named hosts of this year's World Cup, Qatar has come under intense scrutiny over conditions for over two million migrants who work in the country in everything from construction jobs to service industries.
Rights groups say workers face unsafe conditions at work, including extreme heat that has caused deaths, as well as exploitation by employers, despite reforms instituted by Qatar.
Qatari officials say stronger regulations over work conditions have been imposed under the reforms.
They say three workers died in workplace accidents connected to the construction of new stadiums for the World Cup over the past decade, along with 37 other stadium workers who died outside the workplace during that time.
They argue that accident rates at the stadiums are comparable to others around the world.
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