Registration for the 2027 U.S. National Chemistry Olympiad (USNCO) opened on November 1, 2026. A parent or guardian registers the student through the American Chemical Society’s (ACS) USNCO Registration Platform. The biggest change this year is the format: starting in 2027, the Local and National Exams are taken on a secure online platform during proctored, in-person sessions, instead of in handwritten answer booklets.
What Is the USNCO?
The USNCO is the national chemistry olympiad run by the ACS. It begins with a Local Exam organized by ACS local sections. Local results are used to nominate students for the National Exam, and the 20 top scorers on the National Exam attend a two-week Study Camp, where the U.S. team for the International Chemistry Olympiad (IChO) is chosen.
2027 Dates
- November 1, 2026: student registration opened
- February 27 to March 2, 2027: Local Exam window
- April 16 to 18, 2027: National Exam
- July 19 to 28, 2027: International Chemistry Olympiad
The Study Camp dates are listed as TBD. ACS notes that the schedule is subject to change. Each local section chooses its own session date, location, and registration deadline within the ACS window.
Who Can Take Part
- Students enrolled in a U.S. high school (grades 9 to 12) who are under 20 on July 1, 2027, and who graduate no earlier than May 1, 2027.
- Any of these students may take the Local Exam. Only U.S. citizens and permanent residents (green card holders) can be nominated for the National Exam.
- A local section may nominate no more than two students from the same high school for the National Exam.
- Students compete through the ACS local section tied to their high school’s address; home-schooled students use their home address.
How to Register
- The parent or guardian registers. ACS requires a parent or guardian to register each student on the USNCO Registration Platform.
- Registration does not guarantee a seat. The local USNCO Coordinator confirms participation and sends exam details.
- Find your local section. ACS has a coordinator lookup by zip code. Fullerton (92833) falls under the Orange County Section.
- Testing accommodations. ACS asks that all accommodation requests reach the coordinator by December 1, before the Local Exam.
The Orange County Local Exam
For students whose high school is in Orange County, the Orange County Section of the ACS lists its registration period as November 1, 2026, to February 19, 2027. Its Local Exam is being planned for the morning of Sunday, February 28, 2027. Students will bring their own device with the required testing software, and the section says device and software requirements are still pending national ACS guidance. The location and fee are not final; the section plans to email registered families about the fee and payment beginning in mid-January. Other local sections set their own deadlines and dates.
The Orange County Section also offers a separate First-Year Chemistry Exam for students in their first year of high school chemistry. Students who take the Local Section Exam cannot also take the First-Year Chemistry Exam, so the section suggests talking with a chemistry teacher about which one fits.
What the Exams Cover
The Local Exam has 60 multiple-choice questions in 110 minutes. The National Exam has three parts: 60 multiple-choice questions (90 minutes), 8 written problems (105 minutes), and 2 lab practicals (90 minutes). ACS says the content and standards are the same as in earlier years; only the delivery has changed. Multiple-choice questions span stoichiometry and solutions, descriptive and laboratory chemistry, states of matter, thermodynamics, kinetics, equilibrium, oxidation-reduction, atomic structure and periodicity, bonding and molecular structure, and organic chemistry and biochemistry. Only non-programmable calculators without memory are allowed.
ACS is also taking applications for its online USNCO Coaching program until December 14, 2026.
For our AP Chemistry classes, see our AP Chemistry page.
Information checked November 13, 2026.
Sources: American Chemical Society, U.S. National Chemistry Olympiad, Rules & Eligibility, How to Participate, Exam Information; Orange County Section of the ACS, Chemistry Olympiad Pre-Registration 2027.
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