Why does child marriage happen?
At its heart, child marriage is rooted in gender inequality and the belief that girls and women are somehow inferior to boys and men.
Child marriage is a complex issue. Poverty, lack of education, cultural practices, and insecurity fuel and sustain the practice.
But drivers will vary from one community to the next and the practice may look different across regions and countries, even within the same country.
In many communities where child marriage is practised, girls are not valued as much as boys – they are seen as a burden on their family. Marrying your daughter at a young age can be viewed as a way to ease economic hardship by transferring this ‘burden’ to her husband’s family. 
Child marriage is also driven by patriarchal values and the desire to control female sexuality, for instance, how a girl should behave, how she should dress, who she should be allowed to see, to marry, etc.
Families closely guard their daughters’ sexuality and virginity in order to protect the family honour. Girls who have relationships or become pregnant outside of marriage are shamed for bringing dishonour on their family. 
Culture and tradition
Child marriage is a traditional practice that in many places happens simply because it has happened for generations. In some communities, when girls start to menstruate, they become women in the eyes of the community. Marriage is therefore the next step towards giving a girl her status as a wife and mother.
Harmful traditional practices can be linked to each other. In southern Ethiopia for instance, child marriage usually follows the practice of female genital mutilation/cutting, which is considered a rite of passage to womanhood. 
Traditional practices often go unquestioned because they have been part of a community’s life and identity for a very long time. But as Graça Machel, widow of Nelson Mandela, says, traditions are made by people – and people can unmake them.
More than half of girls from the poorest families in the developing world are married as children.  Where poverty is acute, families and sometimes girls themselves believe that marriage will be a solution to secure their future.
Giving a daughter in marriage allows parents to reduce family expenses by ensuring they have one less person to feed, clothe and educate. Families may also see investing in their son’s education as more worthwhile investment. In some cases marriage of a daughter is a way to repay debts, manage disputes, or settle social, economic and political alliances.
In communities where a dowry or ‘bride price’ is paid, it is often welcome income for poor families; in those where the bride’s family pays the groom a dowry, they often have to pay less money if the bride is young and uneducated.
Many parents marry their daughters young because they feel it is in her best interest, often to ensure her safety in areas where girls are at high risk of harassment and physical or sexual assault.
Child marriage can increase in humanitarian crises, such as in conflict or after a natural disaster. When families face even greater hardship, they may see child marriage as a coping mechanism in the face of poverty and violence. Nine out of the ten countries with the highest child marriage rates are considered fragile states. 
 Save the Children UK, Rights of Passage, 2003
 American Jewish World Service (AJWS) and al., Child, Early and Force Marriage and the Control of Sexuality and Reproduction, 2015
 Young Lives, Child Marriage and Female Circumcisions (FGM/C): Evidence from Ethiopia, Policy brief 21, July 2014.
 ICRW and Girls Not Brides, Taking action to address child marriage: the role of different sectors: Economic Growth and Workforce Development brief, 2015.
 As defined by the OCED.