Science Olympiad, sometimes abbreviated as SciOly or SO, is an American team competition in which students compete in 23 events pertaining to various fields of science. The subjects include earth science, biology, chemistry, physics, and engineering. Over 7,800 middle school and high school teams from 50 U.S. states compete with each year. The U.S. territories do not compete. However, several international teams do compete in Science Olympiad tournaments in the U.S.