Child marriage is a widespread violation of human rights. It is an impediment to social and economic development, and it is rooted in gender inequality. The low value placed on girls and women perpetuates the act and acceptability of child marriage in societies where the practice is common. Child marriage is defined as any legal or customary union involving a boy or girl below the age of 18. This definition draws from various conventions, treaties and international agreements, including the Convention on the Rights of the Child, Convention on the Elimination of All forms of Discrimination against Women, Universal Declaration of Human Rights, and recent resolutions of the UN Human Rights Council. While boys sometimes marry young, this paper addresses the practice primarily as it affects girls who make up the large majority of children who are married under 18. If current trends continue, more than 140 million girls will marry early in the next decade or up to 40,000 per day.