The 29-year-old reality star appears wearing a headdress in a couple of pictures from North's "Kidchella" celebration on Saturday.
After the photos went viral, the cultural director of the Redhawk Native American Arts Council, Cliff Matias told Page Six that Kardashian's actions had been "insensitive."
"It's terrible," he said. "It's absolutely terrible that they have no conscience to discontinue to do such things."
Matias added that there was "no way" that Kardashian isn't aware of the controversy surrounding the Washington Redskins' trademarks.
"I just can't believe she would be that insensitive to think it was OK to wear that war bonnet at a kids' party," he continued, "Now you have a celebrity at a kids' party creating a whole new generation of insensitive thinking."
Neither Kardashian or her rep have yet to comment on the incident.