bullying

For

School uniforms reduce discrimination against students who wear cheaper clothes, or who wear the same clothes the next day.

Against

Uniforms only accentuate differences in length, hair color and other physical characteristics. Children consequently judge each other by their physical appearances. One can argue whether it were better if children judged each other by their clothes instead. __source__

Uniforms make students focus more on faces, body shapes, sizes and color. The question is what kind of discrimination is worse. In regard to wealth, one can ignore discrimination, because wealth depends on one's parents. By contrast, body shape, size and color is much more personal. If one were allowed to choose one's own clothes, one could wear clothes (even cheap clothes) that draw the attention away from features that one fears might lead to discrimination. Uniforms deny students the possibility to express what they want to be in what they wear. __source__

When the ability to draw attention on clothing is taken away, students will focus more on expensive gadgets, such as iPods, mobile phones, watches, calculators and sunglasses, on sport clothes and equipment, on expensive food, candy and drinks brought to school or bought at the school cantine (Gatorade), and on how expensive the car is of the parents who pick them up or drop them off. It's much easier to look good in less expensive but well-chosen clothes, compared to the rivalry with gadgets, expensive food, cars, etc. __source__

School uniforms give students just another reason to bully each other, e.g. with comments such as: "pull up your socks" or "tuck in your shirt" or "tidy up your tie". Your assumption that uniforms lead to less peer pressure is not supported by studies into such questions. __source__

The uniform makes the student an easily identifiable and predictable target walking down the same road every day at the same time. __source__