Girls can choose to wear shorts or a skirt. But it hasn't always been so.
In the 1920s female tennis star Suzanne Lenglen caused a stir - just for playing without a petticoat or corsets.
Then Joan Lycett became the first woman to discard her stockings to play in bare legs and ankle socks.
In 1932, Britain's Bunny Austin became the first top male player to wear shorts in tournaments.
But it's all down to personal preference.
If you are wondering how women hold a tennis ball without having a pocket to use, the answer is a ball clip.
It attaches to the waist band and the ball can be clipped into it to hold it secure.