The National Science Olympiad is organized into two divisions of competition: Division B and Division C. Division B serves grades 6-9, while Division C serves grades 9-12. Division A, also known as Elementary Science Olympiad, is for grades K-6 and is more regional in nature with no national tournament. Each division competes separately - while many tournaments may have competitions for both Division B and Division C at the same time and location, some may not and might schedule separate tournaments. Each division has separate events, though some such as Experimental Design may be held in both divisions using different rules. Science Olympiad alumni may refer to the graduate experience of volunteering at tournaments and writing tests as Division D, though this is not an official division.
For more information about each division and their events, refer to the pages below.