Canadian Mike Garrett started the petition to urge the band to call off its Feb. 15 gig after viewing the CNN documentary "Blackfish" by Gabriela Cowperthwaite, The Hollywood Reporter said Friday.
The film questions the safety record at marine parks.
"We've talked things over, and decided not to play at SeaWorld at this time," the Barenaked Ladies wrote on its Facebook page.
"The world has changed and people are seeing places like SeaWorld and Marineland for what they truly are: 'abusement' parks that profit off the suffering of animals rather than the family destinations they make themselves out to be," Garrett said on his website.
The report did not include a comment from SeaWorld.