School uniforms are largely found at religious, parochial and military schools. Dress codes have replaced uniforms at most schools.
More and more private schools are adopting dress codes as opposed to uniforms. You will still find uniforms in religious, parochial and military schools. Perhaps the most famous school uniform is the one worn by boys at Eton College. While it is still worn everyday, the uniforms worn in American schools are a lot less formal, if, indeed, a uniform is worn at all.
One of the reasons a dress code is more popular is that it gives some modicum of self-expression while at the same time maintaining a standard of dress. Oversize clothing, all black outfits, extreme hair styles and other symbols of gangs and fringe activities are simply not on.
This dress code from Foxcroft School is typical of the sort of dress code you can expect at a girls' school:
"Foxcroft's dress code is fairly simple – khaki or black pants or skirts with solid-colored, collared blouses which are tucked in. Shoes (which may not be athletic shoes) must have closed toes and backs. Dress code is required during the Academic Day."
McCallie School offers a quite detailed description of what's acceptable and what's not at that fine all-boys school in a Dress Code Letter:
"Regular school dress requirements/prohibitions are as follows:
1. Students are expected to wear a solid colored dress shirt with tie (tie should be within one inch of top button on shirt), long pants with a belt, visible socks, and shoes.
2. Students should tuck shirts in so that belts are visible.
3. Denim pants are not allowed.
4. Clothing depicting alcohol, tobacco, drugs, or other objectionable material is prohibited.
5. Shoes should be leather and/or canvas. Shoes should be of an approved color. The approved colors are black, blue, brown, gray, green, tan, and white.
6. Sandals, open-toed or backless clogs, and military boots are not permitted.
7. Hair should be kept neat and clean and be out of the eyes, clearly off the collar, and not below the ears. No bizarre or trendy haircuts are allowed. Sideburns should not extend below the ears.
8. Caps or hats may not be worn inside buildings.
9. Facial hair, earrings, body piercing, and tattoos are not allowed.
On Fridays, students may choose to wear the official, royal blue school shirt. The Friday shirt must be tucked in at all times. Those choosing not to wear the Friday shirt must be dressed in regular school attire. McCallie Friday shirts are available for purchase in the school bookstore.
Sweatshirts, hooded or otherwise, must be official McCallie apparel.
Some dress codes are quite strict, almost bordering on a uniform. Others give plenty of room for individual expression. Most schools will have a dress code for formal days such as prize giving. Uniforms for sports and physical education programs are still very much de riguer."