Child marriage is a worldwide priority issue as ending child marriage by 2023 is a target embedded in the Sustainability Development Goal (SDG). The child marriage practice is going on around the world. Based on the latest data 21 % of young women were married as children. in Bangladesh, 38% of adolescent girls are married before the age of 15, and 51% of young women are married before their 18th birthday. Since research on this particular issue is very scanty, this study aims to explain the perception of Secondary School girls about child marriage and provide practice-based recommendations for strengthening the community especially girls to prevent it. According to the law of Bangladesh, the minimum age of marriage for girls is 18 years and for boys is 21 years. Any marriage before these ages can be treated as child marriage. In practice, child marriage is happening in Bangladesh, particularly in urban slums and rural areas. The studies show poverty and ignorance of the parents/ guardians about the consequence of child marriage, less access to sexual & reproductive health services, and prevailing social norms of marriage are the main reasons for child marriage.