Eleanor Waldorf Rose is Blair Waldorf's cold-hearted and often critical mother. She is also the owner of Waldorf Designs. Eleanor's marriage to Blair's father, Harold Waldorf, ended when he left to pursue a gay relationship with Roman, a French male model.

Eleanor is quite focused on her career and is often absent from Blair's life. When she does return, she is often critical of Blair's weight and often seems to favor Serena over her own daughter. Blair's critical self-image and eating disorder seems to stem from her desire to please her mother.

Eleanor is often seen as calculated and cruel, she does what she wants herself; often with no thought what it will do to those around her. She has admitted in the past that Dorota has actually brought Blair up more than she has. Even though, she was very supportive to blair in the 5th Season during her marriage, and she was the one who went looking for Chuck when she believed that Blair marrying Louis was not a good choice. She wants the best for her daughter and loves her, so that at the end of the season she passes Eleanor Waldorf Designs to her.