Women in Saudi Arabia can now travel abroad without a male guardian's permission, royal decrees say.
The new rule announced on Friday allows women over the age of 21 to apply for a passport without authorisation, putting them on an equal footing to men.
Women are also being granted the right to register childbirth, marriage or divorce.
The decision follows a series of high profile attempts by women to escape abroad from the kingdom.
Saudi Arabia has long come under scrutiny over its treatment of women in the kingdom, with activists saying they are often treated as second-class citizens.
The de facto leader, Crown Prince Mohammed bin Salman, has sought to ease social restrictions on women, including lifting a driving ban last year, in a bid to open up the conservative kingdom.
But he has also cracked down on women's rights activists, putting a number of them on trial in recent months.
What is changing?
Saudi's male guardianship system gives husbands, fathers and other male relatives the authority to make critical decisions about women.
Until now, this has meant women there were required to seek those relatives' permission to obtain or renew a passport and exit the country.
But the royal decrees published in the kingdom's official weekly Um al-Qura gazette on Friday stipulate that Saudi passports should be issued to any citizen who applies for it, and that anyone over the age of 21 does not need permission to travel.
The changes allow women for the first time to register their children's births, as well as marriages and divorces.
They also cover employment regulations that expand work opportunities for women. Under the rule, all citizens have the right to work without facing any discrimination based on gender, disability or age.
How are women reacting?
Many Saudi women have taken to Twitter to celebrate the move, with prominent influencer and talk show host Muna AbuSulayman tweeting: "A generation growing up completely free and equal to their brothers."
The first woman to become an envoy for the kingdom, Saudi ambassador to the US Reema bint Bandar Al Saud, also hailed the changes:
"If fully implemented [this is] a big step in letting adult Saudi women take control of their own lives," Kristin Diwan from the Arab Gulf States Institute in Washington DC told the AFP news agency.
Others are wary of the new reforms.
Some conservatives in the country have reacted negatively to the changes, with one woman telling Reuters news agency: "Imagine if your girls grow up and leave you and don't return, would you be happy?"
What restrictions remain?
Despite the latest reforms, other parts of the guardianship system remain in place. These include women requiring permission from a male relative to marry or live on their own, as well as leave prison if they have been detained. They still cannot pass on citizenship to their children, nor can they provide consent for their children to marry.
In a bid to open up the country, Crown Prince Mohammed bin Salman unveiled a plan in 2016 to transform the economy by 2030, with the aim of increasing women's participation in the workforce to 30% from 22%.
However, rights groups have decried his crackdown over the last year on some of the country's leading women's rights activists who had campaigned for the right to drive or win equal rights to men.
These women, including prominent campaigner Loujain al-Hathloul, are currently facing trial and several of them say they have been tortured whilst in detention.
There have been several high profile cases of women seeking asylum in countries such as Canada, citing claims of gender oppression.
The issue hit the headlines in January when 18-year-old Rahaf Mohammed al-Qunun fled Saudi Arabia in a bid to escape to Australia, but ended up in a stand-off at an airport hotel in the Thai capital Bangkok. After international appeals for help, Canada later granted her asylum.
In March, two young Saudi sisters who had been hiding in Hong Kong were granted humanitarian visas in a third country.
In a similar case a month later, another pair of sisters fled to Georgia after seeking international help on Twitter and were eventually relocated to another country.
PUKmedia \ BBC