Can the school tell me how I have to dress?
Yes, up to a point. As with other student rights, your right of personal expression and appearance at school must be balanced with the school’s need to provide a safe and healthy learning
environment. Your school may have a dress code that prohibits clothing items that promote illegal activities or gang affiliations, violence, discrimination, or the use of tobacco, drugs, alcohol or weapons. A dress code may also prohibit items that may disrupt the learning environment because they are sexually suggestive, obscene, lewd or vulgar.
A school may not prohibit dress that is part of the practice of your religion. If your religion requires certain dress, such as a yarmulke or hijab, the school must accommodate you. You may not be deprived of your right to a free public education because of your religion.