The president of the small West African country of Sierra Leone signed a law on Tuesday that banned marriage for children age 18 and younger and would impose steep fines on adult spouses. The move was a victory for activists who had long fought to eradicate the widespread practice.

The new legislation goes further than many other similar laws in Africa, experts said, by penalizing people who enable the marriage — like the parents, the officiant and even the wedding guests — in addition to the husband.

There were about 800,000 girls under the age of 18 who were married in Sierra Leone, UNICEF reported in 2020, which is about a third of the girls in the country. Half had been married by the time they turned 15. About 4 percent of boys are wedded by 18, according to Human Rights Watch.

Under the new law, those married as children can seek financial compensation. They also have a path out of their marriages: petitioning for an annulment.

Betty Kabari, a researcher at Human Rights Watch who focuses on women’s rights and sexual health in Africa, praised the approach of penalizing those who abet the marriage, saying, “The strongest aspect, to me, is noting that a child does not get married in isolation.”

How widespread is child marriage?

Every year, at least 12 million girls under the age of 18 marry, according to the United Nations. More than 650 million girls and women were married as children.