The school uniform is designed to provide a sense of school identity while recognizing climatic and cultural restrictions. Parental support of the school uniform policy is greatly appreciated.

Students in Years 2 to 13 are to wear the school uniform. This expectation will be strictly enforced by the teaching faculty and administration. Students are expected to come to school dressed in their uniform and to maintain a well-groomed appearance. Students arriving at school not properly dressed may not be allowed to attend class. They may be asked to return home, or parents may be called to bring the proper dress to school.

School uniforms may be purchased from the school office. If you prefer to have uniforms made, please purchase the fabric from the school. The school will give you a pattern for the uniform. The school’s fabric must be used, and the pattern must be followed.

The uniform consists of a white shirt or polo type shirt with the school's logo on the chest pocket, along with beige trousers, shorts or a skirt. Shoes should be trainers, sandals, sneakers or dress shoes worn with white socks. No flip-flops or high-heeled shoes are allowed.

Provocative or unusual hairstyles or colours are not considered appropriate for a school setting. Hats and caps may not be worn indoors.

The wearing of excessive or valuable jewellery or watches is discouraged. Lanna International School Thailand accepts no responsibility for any jewellery or other items (for example, mobile phones) brought to school by students.

A recent addition to the school uniform is a dark green hooded top (pictured left) for students to wear during the cooler months. Students should not wear other sweaters/pullovers in school.

The Physical Education (PE) uniform for both boys and girls consists of the house shirt (in the designated house colour, with the school logo), athletic shorts or pants (with the school logo), and athletic shoes (or trainers). Students are encouraged to wear a hat or baseball-style cap during PE. For some activities, students may need special PE clothes or equipment, for example, swimwear, towels, and swimming goggles.

Students change into their PE uniforms before their Physical Education class and change back into the school uniform after PE. Students may not wear the same clothes during PE and during their regular classes.

If students do not have their PE uniform, they will not be allowed to participate in PE that day. In the calculation of grades, this will count as an absence from the PE class.