The U.S. National Chemistry Olympiad is one of the most respected opportunities for high school students in the United States to test their chemistry skills at the highest level. American Chemical Society (ACS) has sponsored the program since 1984, and it remains one of the clearest ways for a student to signal serious academic ability to top universities.
Beyond the prestige, USNCO is genuinely challenging. Strong performance can lead to an invitation to the Study Camp and, ultimately, a spot on the four-person team representing the United States at the International Chemistry Olympiad (IChO). This guide walks through eligibility, the structure of each round, what to study, and how to build a preparation plan that works.
What Is the US National Chemistry Olympiad
USNCO is a multi-tiered chemistry olympiad-style competition open to high school students across the country.
It is designed to challenge students well beyond typical classroom chemistry, giving them a chance to explore the subject in depth, solve genuinely difficult problems, and earn recognition for their work.
For the 2026 cycle, student registration opened October 6, 2025, and the program runs through four stages: the Local Exam in late February through mid-March, the National Exam in April, the Study Camp in late May through mid-June, and the International Chemistry Olympiad in July.
Eligibility and Registration
To participate, a student must be enrolled in a U.S. high school in grades 9 through 12. Homeschooled students are eligible as well, provided they meet equivalent academic standards.
Students must be under 20 years old as of July 1 of the competition year, and while U.S. citizenship is not required, participants must be legal residents attending a U.S. high school, which includes students on F-1 visas. Students who have already represented the United States at IChO are not eligible to compete again, though prior USNCO participation without advancing to IChO does not disqualify a student from trying again.
Registration begins at the school level. A chemistry teacher or school official typically coordinates registration for the Local Exam through the student's ACS Local Section. From there, the Local Section Coordinator nominates top performers to sit the National Exam.
Registering does not guarantee a spot in the next round, since advancement depends on how a student performs relative to others in their local section.
How the Competition Is Structured
The Local Exam
Held each spring, the Local Exam is a multiple-choice test covering general, organic, physical, and analytical chemistry. It is administered through ACS Local Sections rather than at the national level, and coordinators use the results to decide which students move forward. Because thousands of students sit this round nationwide, a strong showing here is the first real test of a student's preparation.
The National Exam
More than 1,000 students sit the National Exam each April, often at a local university or college hosted by an ACS Local Section.
This round has three parts:
A multiple-choice section,
A free-response section that asks students to explain their reasoning in depth,
A lab practical where students carry out real experiments and analyze their own data.
The lab section tends to be the part students remember most, since it is the only stage that tests hands-on skills rather than pure content knowledge.
Study Camp
The 20 highest scorers on the National Exam are invited to a two-week Study Camp, where they train intensively and are evaluated further. This stage runs through late May and early June.
The International Chemistry Olympiad
From Study Camp, the top four students are selected to represent the United States at IChO in July. They travel with mentors who translate the exam, inspect host laboratories, and help arbitrate scoring, alongside opportunities to connect with student competitors from other countries.
What to Study
Preparation naturally splits into two stages. For the Local Exam, students should have a firm grip on general chemistry topics like atomic structure, periodic trends, bonding, stoichiometry, and thermochemistry, along with foundational organic chemistry, physical chemistry, and analytical chemistry.
Students advancing to the National Exam need to go further. This means diving into:
Advanced organic chemistry, including reaction mechanisms and spectroscopy,
Advanced inorganic chemistry topics like coordination chemistry and crystal field theory,
Physical chemistry areas such as quantum chemistry and statistical mechanics,
Analytical techniques like chromatography and instrumental analysis.
A working knowledge of biochemistry, particularly amino acids, enzyme kinetics, and metabolic pathways, rounds out National Exam prep.
Building a Study Plan That Works
Strong performance on USNCO rarely comes from cramming. It comes from a study plan built well in advance.
We have a blog to help you maintain a balance with school and other commitments.
Start With The Fundamentals
Before tackling advanced material, make sure atomic structure, periodic trends, stoichiometry, and thermodynamics feel second nature. AP Chemistry textbooks are a solid resource here, since they cover much of the same ground as the Olympiad tests.
Set Goals
Set specific, measurable goals for each study session rather than studying in a vague or open-ended way, and build a consistent weekly schedule around the times you focus best. Make sure your plan covers physical, organic, inorganic, and analytical chemistry, and lean into the areas that challenge you most rather than avoiding them.
Practice With Old Exams
Past USNCO exams show you exactly how questions are structured, and the competition has been known to reuse questions, so familiarity pays off directly. Review every mistake carefully rather than moving on quickly, and periodically sit a full practice exam under real time constraints so the actual test day feels familiar rather than overwhelming.
Collaborate With Others
Finally, do not try to prepare in isolation. A teacher, mentor, or study group can help you work through concepts that are not clicking, and explaining ideas to peers often reinforces your own understanding faster than studying alone.
A lot of USNCO prep is self-directed, and that is exactly where a good mentor makes the difference between studying hard and studying well. Working with someone who has been through rigorous STEM competition preparation before can help you spot gaps in your understanding faster, build a study plan that actually fits your schedule, and stay accountable when motivation dips in February.
Where Mentorship Fits In
If you are building out a broader STEM competition strategy, whether that includes Olympiad prep, a science fair project, or both, a free consultation with one of our academic advisors can provide you with a roadmap to success.
Other Olympiads
If you're interested in doing other Olympiad competitions, you could look into the Genius Olympiad and the International Research Olympiad.
