The network did not air the memorial to remember the time when the first plane hit the World Trade Center in September 2001, but instead broadcast an interview with Keeping Up with the Kardashians star Kris Jenner on The Today Show.
A moment's silence was held at Ground Zero in New York, with victims' families, the NYPD, FDNY and Port Authority Police in attendance.
President Barack Obama and Michelle Obama also observed the moment at 8.46am at the White House.
ABC's Good Morning America, CBS This Morning and other cable networks broadcast the moment of silence.
Jenner appeared on The Today Show talking about the upcoming season of her show and her new breast implants, according to TV Newser.
However, NBC News did broadcast the moment of silence in New York City.
Many people criticised the network's decision on Twitter, with one user commenting: "The Today Show has Kris Jenner on, no mentions of 9/11. Is 11 years the expiration date of caring? Terrible."
Another stated: "The fact that Kris Jenner is a guest on the today show on 9/11 seriously makes me doubt humanity."
NBC was recently criticised for its lack of coverage of the Paralympic Games.