Mrs. Wexler's treatment of Turtle is quite un-mother-like. Mrs. Wexler often ignores or even forgets about Turtle; when she does pay attention to her, she usually disapproves of her and often thinks unkind thoughts toward her or belittles her. At all times she gives her daughter Angela, "her perfect child," preference.

When Grace Wexler first inspects the apartment, she comments that the third bedroom, which her husband suspects might be a closet, "would do just fine for Turtle." In chapter 3, while Angela is having a fitting of her wedding gown in their apartment, Turtle decides not to share the "horror story" she has heard about the Westing house. She tells herself that her mother wouldn't care if she was murdered or went insane. When her mother criticizes Turtle's Halloween costume and asks her why she must always make herself so ugly, Turtle spouts a rude remark about Angela's wedding dress, and Grace tells her to shut her mouth. She rises as if to strike Turtle, but catches herself. She has never hit her, but she feels the temptation.

In chapter 9, Mrs. Wexler begins treating Turtle well. She calls Turtle "dear" and begins to fix her hair. She even suggests that Turtle wear her party dress because she looks so pretty in pink. This arouses Turtle's suspicion, since her mother never calls her pretty. She realizes that her mother is treating her with kindness only because she wants her to share her clues. When Turtle refers to her bedroom as a closet, Mrs. Wexler tells herself that being nice to "that ungrateful child" isn't worth it.

Although Mrs. Wexler is Turtle's mother, she doesn't display motherly affection toward Turtle, only toward her favorite daughter, Angela.