Nepal's supreme court has ruled that women under 35 years of age will not need the permission of their parents or husbands to apply for a passport.
The law was introduced to prevent trafficking of women.
The ruling was in response to petitions by two women saying that the existing law was discriminatory and contradicted the country's constitution.
The law was introduced three years ago to curb the trafficking of women.
The ruling is the latest in a series that the court has made on women and children in Nepal.
In September, it ordered an end to discrimination against women during their menstrual cycle.
The court also ruled that children must be granted citizenship even if their parents are unknown - in response to petitions demanding citizenship for children of sex workers.
On Tuesday, the court ordered the prime minister's office, the interior ministry and the women's ministry to immediately end the practice whereby women under 35 needed to get the permission of their parents or husband to apply for a passport.
Judges Badri Kumar Basnet and Balram KC said the practice was unfair as men did not have to follow the same procedure.
"This provision is against the equal rights guaranteed to women by the constitution," the judges said in their ruling.
The law was introduced as a measure to prevent trafficking of women to India.
Women's groups say that thousands of women are trafficked to India every year and forced to work as sex workers.
The groups have however, supported the court ruling.
"The previous practice discriminated against women since it robbed them of their right to mobility and to self determine," Sapana Pradhan Malla of the Forum for Women, Law and Development told the Associated Press.
"The state had failed to treat men and women equally," she said.
In September, the supreme court ordered the government to stamp out the practice of keeping women in cow-sheds during their menstruation cycle that is practised in some western areas of the country.