Schools often have a dress code that requires school uniforms or that limits clothing styles—such as policies of no tank tops, shorts, low-cut tops, pants worn below the waistline, or suggestive, provocative, or controversial messages. Some schools extend these dress code policies to hairstyles, headwraps, hair color, and facial hair.

These policies are sometimes challenged by students on free speech grounds (under the First Amendment to the U.S. Constitution) and on discrimination grounds. Schools are required to meet a high burden to justify restricting their students’ right to freedom of speech.

Each school policy and claim of a violation of law must be evaluated on a case-by-case basis but schools are generally allowed to restrict clothing, speech, and hairstyle choices only if they would likely disrupt the educational environment of the school and interfere with school activities—including by causing tension and discord among the students or teachers.

In California, schools have the authority to implement dress codes, which may include the requirement of school uniforms or restrictions on certain types of clothing and personal appearance, such as hairstyles and facial hair. However, these policies must balance the school's interest in maintaining a conducive educational environment with students' rights to free speech and expression under the First Amendment. When dress code policies are challenged, courts typically use the 'Tinker' test, derived from the Supreme Court case Tinker v. Des Moines Independent Community School District, to determine whether the restrictions are justified. This test allows schools to restrict student expression only if it would materially and substantially disrupt the operation of the school. Additionally, dress codes must not be discriminatory on the basis of race, gender, religion, or other protected characteristics under federal and state anti-discrimination laws. Each case involving a challenge to a school dress code policy is assessed individually to ensure that the restrictions are appropriate and not in violation of students' legal rights.