“Why is the NFL getting massive tax breaks while at the same time disrespecting our Anthem, Flag and Country? Change tax law!” Trump wrote in a post on Twitter.
It was not clear what exactly Trump was demanding since the NFL gave up its tax-exempt status in 2015. The White House did not reply to requests for comment.
“The idea that we received some sort of tax break is not true so there is nothing really here to give up,” the NFL’s chief spokesman, Joe Lockhart, told reporters in a teleconference.
Trump, a Republican, last month called on NFL team owners to fire players who kneel during the “Star-Spangled Banner” to protest police violence against black Americans.
The protests have continued through the season, with some players taking a knee when the U.S. national anthem is played before each game and others standing arm-in-arm in a show of solidarity.
Critics contend the president is fanning the controversy to distract from issues including devastation in Puerto Rico after Hurricane Maria, tensions with North Korea and difficulties in pushing healthcare and tax overhauls through U.S. Congress.
U.S. Vice President Mike Pence walked out of a Sunday NFL game in Indianapolis after some players knelt. Critics suggested he had planned it as a publicity stunt.
The majority of NFL players are black, while Trump won the presidency with less support from black and Hispanic voters than any president in at least four decades.