Previously, countries competing at football's most prestigious international tournament were allowed to select only 23 players in their squads.
However, due to the unusual timing of this year's tournament and with concerns still present with regards to coronavirus, FIFA have confirmed that the number of squad members has been increased by three.
On matchdays, nations can have no more than 26 people - up to 15 substitutes and 11 team officials - allowed to sit on the bench, and one of those officials must be a team doctor.
All 32 nations competing in Qatar are required to submit their final squads of 26 players before the deadline on November 13, eight days before the tournament begins.
The 2022 World Cup is the third major international football tournament which has seen squad sizes for competing nations increase over the last 12 month, after UEFA permitted countries to select 26-man squads for Euro 2020, while CONMEBOL allowed 28-player squads for the 2021 Copa America.