It's International Day of the Girl - a day to bring attention to girls' rights and the challenges that they face around the world.
Being unable to get an education, being made to marry while you're still a child, or simply not being given as many chances at things as boys - these are just some of the difficulties girls can face.
It can happen to girls in countries all around the world but some can be more of a problem in certain places.
For example in the UK, everyone has access to schools and an education - it's no different if you're a girl.
But in other countries it can be hard for girls to go to school - their family might not be able to afford it or they might want them to stay at home or get married instead of completing their studies.
International Day of the Girl was set up by the United Nations - or UN as it's often called - a worldwide organisation that brings countries together to talk about world issues.
To mark the day the charity CARE International has been asking schoolgirls what they'd change if they ruled the world.
We also want to know what you would do if you were in charge. Let us know in the comments below.
Footage courtesy of Toby Madden/CARE International