Carri Williams of Sedro-Woolley was also found guilty of the manslaughter of Hana Williams, 13, KOMO-TV in Seattle reported. Her husband, Larry, was convicted of manslaughter but the jury was unable to agree on the homicide charge.
The couple could receive life sentences.
Medical examiners found Hana died of hypothermia and malnutrition, and investigators said her parents beat and starved her and locked her outside to punish her.
Carri Williams on the witness stand denied mistreating her daughter.
"I never treated my daughter like a dog," she said.
She suggested Hana "unintentionally killed herself" by not eating.
Larry Williams' lawyer, Rachel Forde, said he plans to appeal the manslaughter conviction.