Engaging Men and Boys to End the Practice of Child Marriage explores how unequal gender norms uphold this practice and through program examples identifies the ways men and boys are helping to prevent child marriage and mitigate its consequences. Community norms around gender and age inequality, the low value of girls and women, and acceptance of patriarchy and male sexual entitlement to females lie at the root of child marriage. Ending this custom requires communities to collectively dismantle these discriminatory norms and replace them with new, equitable norms. The programs and approaches highlighted in this review have worked with men, boys, and their communities to shift their attitudes and behavior to encourage gender equality and discourage child marriage.