The seven-time Emmy Award winner is to play a retired, high-powered business executive and the mother of Brooke Shields' character Wendy.
Moore's first appearance on the series will be in the show's Season 2 premiere Sept. 24, NBC said.
"I'm fortunate to have had a front row seat to the evolution of working women on television," Moore said in a statement. "It's been great fun to watch the strong female characters of 'Lipstick Jungle' go at it week after week. I absolutely adore Brooke and I'm delighted to be a part of a show which is so well written."
"I am excited and extremely honored to have an actress of Mary Tyler Moore's stature and talent join our show," Shields added.
Celebrity Families of 2014 [PHOTOS]