The observation supports more opportunity for girls and increases awareness of gender inequality faced by girls worldwide based upon their gender. This inequality includes areas such as access to education, nutrition, legal rights, medical care, and protection from discrimination, violence against women and forced child marriage. The celebration of the day also "reflects the successful emergence of girls and young women as a distinct cohort in development policy, programming, campaigning and research."
International Day of the Girl increases awareness of issues faced by girls around the world. Many global development plans do not include or consider girls, and their issues become "invisible." More than 62 million girls around the world had no access to education, as of c. 2014, according to USAID. Worldwide and collectively, girls ages 5 to 14 spend more than 160 million hours more on household chores than boys of the same age do. Globally, one in four girls are married before age 18. On October 11, 2016, Emma Watson, a United Nations Women's Goodwill Ambassador, urged countries and families worldwide to end forced child marriage. Many girls around the world are vulnerable to acts of sexual violence and the perpetrators often go unpunished.
The Day of Girls helps raise awareness not only of the issues that girls face, but also of what is likely to happen when those problems are solved. For example, educating girls helps reduce the rate of child marriage, disease and helps strengthen the economy by helping girls have access to higher paying jobs.
The International Day of Girls initiative began as a project of Plan International, a non-governmental organization that operates worldwide. The idea for an international day of observance and celebration grew out of Plan International's Because I Am a Girl campaign, which raises awareness of the importance of nurturing girls globally and in developing countries in particular.
Each year's Day of Girls has a theme; the first was "ending child marriage", the second, in 2013, was "innovating for girls' education", the third, in 2014, was "Empowering Adolescent Girls: Ending the Cycle of Violence," and the fourth, in 2015, was "The Power of Adolescent Girl: Vision for 2030." The 2016 theme was "Girls' Progress = Goals' Progress: What Counts for Girls," the 2017 theme was "EmPOWER Girls: Before, during and after crises," and the theme for 2018 was “With Her: A Skilled Girl Force.”
Various events to promote the Day of Girls are planned in several countries.
In 2016, London held a Women of the World (WOW) festival where 250 London school-aged girls were paired with women mentors. Also in 2016, President of the United States, Barack Obama, issued a proclamation supporting an end to gender disparity.