Anna Stevenson (born on October 15th) is Abby Stevenson's twin sister. She is shown to be a very gifted musician who spends hours practicing her violin.
Anna is described as having short curly brown hair (which she has worn short since elementary school) and wears different glasses frames from Abby.
She was born in Long Island, New York but moved to Stoneybrook with Abby and her mother Rachel Stevenson after her father was killed in an accident when she was nine years old.
She is Jewish, and her Hebrew name is Hannah.
Anna was asked to join the Baby Sitters Club along with Abby, but she declined due to her commitment to playing the violin the school orchestra.
In Book #104, Anna is diagnosed with scoliosis and has to wear a brace underneath her clothing for 23 hours a day for 2 to 3 years. She is x-rayed for her scoliosis by Dr. Abrahams every three months.
Scoliosis is fairly common. About 1 in 100 people have scoliosis. Anna's best friends in Long Island are Roxanne and Carley. She is very close to Shannon Kilbourne. In first grade, she and Abby were asked to wear two different colors to tell them apart. Her code color was red. Anna was born first. She does not like video games. She is good at imitating Abby's allergies.