Tomobiki High School (友引高校, Tomobiki kōkō?, High School of Good Day for Business and Lawsuits), or just Tomobiki High, is a high school located in Tomobiki-cho. It is also the school Ataru, Lum, Ryūnosuke, Shūtarō, Shinobu and Lum's Stormtroopers attend.
Tomobiki High-school is a two-floored school with an attic and a clocktower. Classroom, where Ataru, Lum and others attend is located in the second floor's right side (if viewed from front door). School seems to be shaped like the letter H when viewed from above. It is surrounded by trees and has large gym behind the main building. There is also a greenhouse, where some students grow tomatoes.