Most all schools in Japan have school uniforms, in both public and private schools. Every school has a different style of uniforms which changes seasonally, and some teens even choose their school for its uniforms. "East Boy" would be a good example of a store that is getting a lot of attention from teenage girls. If you go to a school that does not have uniforms, but you want to buy and wear one anyway, it can easily be done.
      There are different opinions about uniforms. Some say they would rather wear casual clothes, while others say they want to wear uniforms so that they do not have to deal with choosing clothes everyday. Right now, uniforms are becoming somewhat like casual clothes because you can color-coordinate them. This is a fashion mostly among junior and senior high students.