The exotic fruit appears on a list of banned items alongside fireworks and weapons.
The ban has been issued after it was feared fans of the band Glass Animals, who are due to perform at Leeds and its sister festival Reading, would bring hundreds of pineapples into the site at Bramham Park.
Glass Animals reference pineapples in their lyrics and have decorated their sets with the fruit during previous festival appearances.
However, the group's drummer Joe Seaward denounced the decision as 'fruitist' and questioned why other large exotic fruits, such as watermelons, are permitted.
But organisers did add that the decision was 'slightly tongue-in-cheek'.
Other forbidden items include drones and glassware.