The Cambridge Chemistry Challenge (C3L6) is a global challenge for high school students co-sponsored by the Department of Chemistry and St Catharine's College at the University of Cambridge. It is officially recommended by the University of Cambridge as a high school academic program. C3L6 is a highly valued chemistry challenge for UK high schools, with over 10,000 students participating each year, and is often used as a pre-test for the UKChO (UK Chemistry Olympiad). It is aimed at high school students up to Year 11 and designed to extend chemistry knowledge in a challenging but fun way.

C3L6 is based on A-level chemistry knowledge, but is more diffcult than A-level and examines students' ability to apply their A-level chemistry knowledge in a flexible way. It is a highly rewarding challenge for students who want to explore the field of Chemistry further and its results are highly sought after by the world's leading universities. In the UK, the C3L6 invites no more than 60 top students each year to a residential camp at the University of Cambridge. Designed and taught by Cambridge professors, the camp aims to enhance the academic ability of young elites in Chemistry and to encourage and help outstanding students to understand and choose to study at Cambridge in the future.