Action Girl: Rarely shies away from action. Even injured, she still wants to be the one to take people down.
Adaptational Attractiveness: In the books that the series is based on, Jane Rizzoli is consistently described as plain or average looking. This is a significant characteristic, as she tends to have an irrational jealousy and dislike of beautiful women. But here, she's being played by the gorgeous Angie Harmon (though Harmon has played Jane as a little more rough and tumble as time went on).
Ascended Extra: Rizzoli is actually a secondary character in "The Surgeon", the first book in the series, and author Gerritsen had planned to kill her off before positive reader feedback changed her mind.
Berserk Button: Harm or threaten her family or Maura and she will show you why she's the top homicide detective in Boston PD.
Middle Child Syndrome: She's usually overlooked by her mother in favour of older brother Tommy or little brother Frankie.
Obfuscating Stupidity: It turns out she was accepted to BCU, but ended up not going because of her family situation. She also pretended not to know anything about chess when she was the one who taught Tommy how to play.
Ambiguously Bi: Even discounting the ton of Les Yay she has with Jane, she's put an awful lot of thought into what kind of women she'd be into if she were a lesbian.
Ascended Extra: Isles doesn't exist at all in "The Surgeon", but when she makes an appearance (in "The Apprentice"), she's a minor character until her role enlarges to be almost equal with Rizzoli in most books, or the primary character in several.
Intelligence Equals Isolation: Maura reveals that her childhood wasn't exactly parties and ponies in "I'm Your Boogie Man." In her own words, "there was a lot of benign neglect" - her parents had their own lives to lead that frequently didn't involve the mundane details of parenthood, and they didn't much care what Maura did as long as she kept good grades. As a result, Maura buried herself in schoolwork, to the point that she gave them the brochures to send her away to boarding school. At ten years old.
Morality Pet: A minor and not always effective one to her biological father Paddy Doyle Jr, a reputed mobster and killer. Paddy does seem to think she is the only good thing he's ever done and when his father, Paddy Sn. ia getting ill, he asks Maura to help him get a compassionate release from prison and stay with Maura.
Screw the Money, I Have Rules!: Maura turning her back on the high society scene to work as a medical examiner. When Jane calls her out on her privileged background, she demonstrates quite convincingly that she "has [their] backs," using her connections to obtain several vital clues to the murder.
Big Secret: She was going around taking up any odd job she could find and acting funny any time money is mentioned. Her husband cheated on their taxes and left her holding a $27,000 debt. She doesn't want to let Jane and Frankie know so she can keep him looking good for them, but they find it out.