The USA Biology Olympiad (USABO) is the national biology competition for United States high-school students, administered by the Center for Excellence in Education (CEE). It runs in stages — an Open Exam, a Semifinal Exam, and a residential National Finals — narrowing thousands of entrants down to the top four, who form Team USA at the International Biology Olympiad (IBO). It tests college-level biology far beyond the usual high-school syllabus.
Last updated 14 October 2026, checked against the organiser's official pages.
Sources: USABO 2027 calendar (CEE) · About the exams (CEE) · Guidelines and eligibility (CEE)
A short entry exam taken at school by thousands of students each year. It screens the field down to a semifinalist group and is where almost every USABO journey begins.
A longer, harder exam for the students who clear the Open Exam. Performance here decides who advances to the National Finals.
A residential round for the top finalists that adds practical laboratory examinations to the theory. The leading finishers are named to Team USA.
The top four finalists form Team USA and represent the United States at the International Biology Olympiad (IBO) against 75+ countries.
USABO is open to United States high-school students (typically grades 9–12). Students must be US citizens or permanent residents to advance past the Open Exam to the Semifinal and beyond; the Open itself is open to any grade 9–12 student at a registered US school. No prior olympiad experience is required to sit the Open Exam — a strong honors or AP Biology foundation is the usual starting point.
The syllabus spans college-level biology; the standard reference is Campbell Biology. Core areas include:
See the full USABO syllabus and past papers.
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