Grandma Crowley is the "dearly departed" mother of Thelma Harper (in flashback sequences). Her first appearance was in a flashback in the NBC version of the show, grumpily talking to Mama over the phone. In this first appearance, Thelma relives her 30th birthday, in which her mother cancels on her without any hesitation. She also puts down her husband, and calls him a loser. She is shown through this to be mean and critical of her daughter, and manages to disappoint her on her birthday.
In her 2nd appearance in the CBS version, she was skinnier and appeared as a ghost, haunting Mama. She was excessively critical, grim, and tried to control Mama throughout the episode. It was said that it was something Mama had to deal with, growing up as well. Grandma Crowley had apparently acted the same way when Thelma was being brought up by her.
She was also played by Vicki Lawrence.