TMZ reported the actress died at her home in Los Angeles but other details remained unclear.
Wallace won an Emmy for outstanding voiceover performance on “The Simpsons” in 1992.
Born in Creston, Iowa, she moved to New York after graduating college and worked in off-Broadway productions. The role of the receptionist on “The Bob Newhart Show” was written specifically for her after she had appeared numerous times on “The Merv Griffin Show.”
After “Bob Newhart,” she went on to appear on several game shows and on “Alf,” “Full House” and “Bewitched” as well as “Murphy Brown,” “The Brady Bunch,” “Taxi” and “Murder, She Wrote.”
She appeared in more than 100 episodes of “The Simpsons” as Bart Simpson’s teacher, who eventually marries Ned Flanders.