The European Court of Human Rights has ruled that Turkey denied a woman her "right to life" by failing to prevent her murder by her son-in-law.
It is the first time the court has ruled against a state for failing to protect someone from domestic violence.
The case was brought by the murdered woman's daughter, Nahide Opuz, who had told police her mother was in danger.
The court in Strasbourg ordered Turkey to pay her more than 36,500 euros ($50,670) in damages and legal costs.
Amnesty International says that every year, dozens of women are murdered by relatives in what are sometimes known as honour killings.
Ms Opuz told the court she and had mother had repeatedly informed the Turkish police that their lives were in danger and had appealed for protection at least four times between 1998 and 2002, including a month before her mother died.
They suffered life-threatening injuries from several incidents of abuse in that period, including when Ms Opuz was stabbed seven times by her ex-husband and when he ran them both down in his car.
He was sentenced to three months in prison, later commuted to a fine, for the car attack, and was fined 385 euros for the stabbing, the court said.
After shooting his mother-in-law, Ms Opuz's ex-husband was sentenced to life in prison by a Turkish court. However, he was released pending an appeal on the grounds that he had committed murder to protect his family's "honour".
The court found there had been a violation of Article 2 of the European Convention on Human Rights - the right to life - because the Turkish authorities failed to take action after being repeatedly alerted about the violent behaviour of the dead woman's son-in-law.
Article 3 - the prohibition of torture and of inhuman and degrading treatment - had been violated when the state failed to protect Ms Opuz from his violent and abusive behaviour, it found.
It also said Article 14 - the prohibition of discrimination - had been violated because the violence suffered by the applicant and her mother was "gender-based", which amounted to a form of discrimination against women.
"The general and discriminatory judicial passivity in Turkey created a climate that was conducive to domestic violence," the court said.