Me What to Wear?
Yes, but only if the school has a uniform clothing policy, to which you agreed when you enrolled, or if you are wearing clothing with "indecent, obscene, or lewd" messages or which that causes a "substantial disruption" at school or school-related activities. It may also ban clothing that promotes drug use.
Of course, you always have the right to wear clothing expressing a political opinion such a T-shirt protesting U.S. involvement in foreign wars, endorsing or criticizing a particular politician, or in support or opposition of a social issue.
The school cannot have dress codes that are explicitly discriminatory. That means that although dress codes can specify the kinds of apparel that are acceptable, these requirements should not differ based on students' sex or their race. Schools can't base either a dress requirement or its application of the dress code on sex stereotypes -- generalizations concerning what kinds of apparel or look is acceptable for a boy or a girl.
For example, a school dress code can't require girls, and only girls, to only wear skirts or dresses and boys, and only boys, to wear pants or a jacket and tie.
The same goes for ceremonial events and special occasions, like prom, yearbook pictures, or graduation.
A school will specify "formal clothing," or even "gowns or tuxedos," but it can't require that girls, wear gowns or that boys, and only boys, wear a tux.
Thought today's dress codes are unlikely to be overtly race-based, there can also be stark racial overtones.
For example a charter school in Massachusetts banned all hair extensions, a style predominantly worn by Black girls. The school also prohibited 'Unnatural style of hair" which really means to wear it up like an afro of "more than 2 inch in thickness or height." The policy therefore effectively prohibits countless black students of either sex from wearing their hair "naturally" while not cutting it very short -- creating it perfectly clear that the school is concerned about distracting versus being distractions.
This type of race-sex discrimination is prohibited.