Dawn Atwood is a fictional character on the FOX television series The O.C., portrayed by Daphne Ashbrook. She is the mother of Trey and Ryan Atwood.

Dawn has a history of alcoholism and of forming relationships with abusive men who also drink, including her boyfriend in the pilot episode A.J. and ex-husband Frank Atwood. She admitted to Ryan that she had Trey young and "didn't know what [she] was doing" when first married Frank, implying that it may have been a shotgun marriage. They lived in Fresno, California but moved south to Chino after Frank was arrested. It is unclear when she and Frank divorced.

Dawn is an expert card sharp, and has passed on this knowledge to Ryan. She used to smoke, a habit which Ryan picked up, but has not been seen with a cigarette since becoming sober.

Dawn first appeared in the pilot episode, where she arrived at a Los Angeles area courthouse to collect Ryan, who had just been released after he and Trey stole a car. Back at their house, Dawn proceeded to argue with Ryan and her then-current boyfriend A.J. about the theft. Eventually, she threw Ryan out of the house, but not after Ryan is physically assaulted by A.J. When he returned later with Sandy Cohen, the house was empty. Dawn and A.J. had moved out, and Dawn had only left a note for Ryan. Sandy and Kirsten Cohen hired a private investigator to track her down. When they found her, she seemed genuinely regretful about having abandoned Ryan and returned to the Cohen household to try to repair her relationship with him. However, at a charity casino evening she got drunk again and caused a scene. Realizing she was unable to look after herself, let alone Ryan, she decides to leave, knowing that Sandy and Kirsten were better equipped to care for Ryan than she was.

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