A dozen countries allow rapists to avoid prosecution by marrying their victims, UN Women said in its flagship annual Progress of the World's Women report.
"We have seen great progress on eliminating discrimination against women in laws, however it is no accident that family laws have been the slowest to change," Phumzile Mlambo-Ngcuka, executive director of UN Women said in its foreword.
"The shocking pervasiveness of intimate partner violence means that statistically, home is one of the most dangerous places to be for a woman."
Nearly one in five women aged 15 to 49 globally experienced physical, sexual or emotional abuse from a former or current partner or spouse in the previous year, the report found, describing violence against women "serious and ubiquitous."
From Iraq and Malaysia, women are ramping up pressure to abolish marry-your-rapist laws after Tunisia, Jordan and Lebanon scrapped similar articles in 2017.
Family law governs matters such as women's right to choose who and when to marry, provides the possibility of divorce and shapes women's access to family resources, it said, calling for policy reform to better protect women.
"If a woman is forced to have sex within marriage ... in 58%of countries that is not recognized as a criminal offense, with the assumption that sex within marriage is always by consent," said Shahrashoub Razavi, the report's chief researcher."This is quite an eye-opener that we still have a long way to go in terms of legal framework," she told the Thomson Reuters Foundation.