Joan Ross is the oldest sister of Maryellen Larkin. Joan is seventeen at the start of the series and finishing her last year of high school, "nearly all grown up." She is also very bossy and take-charge. She finds Maryellen messy, klutzy, sloppy, and tomboyish in comparison to her "crips and clean" look. However, she still cares for her sister and doesn't begrudge her attitudes. Maryellen thinks of her in part as a finicky fussbudget. She sometimes calls Maryellen with rhymes or variations to her nickname, such as "Ellie-jelly", "Ellie-deli," or "Ell-a-reenie." Joan is very cross and snappy if she is woken up too early. She does not want to make a large fuss about her wedding or marrying Jerry; to her, a wedding is one thing and a marriage another. She does, however, initially let her mother have the wedding "her" way but finally speaking up about how she thinks her mother is going overboard and stressing herself out over it. Joan loves books as much as she loves Jerry; Kay thinks of her as a bookworm, even implying (annoyed) that she would marry on the steps of the public library. She loves various authors (such as Emily Dickinson--her favorite poet--and Louisa M. Alcott). She is a terrible cook and Carolyn remarks she would burn water, as she gets distracted by her books while cooking. She later decides--before her marriage--to attend college and study to become a teacher, rather than settling into expectations after marriage of only being a housewife.