The 2021 CS Autumn Classic International was held on September 16–18, 2021 in Montreal, Quebec, Canada. It was part of the 2021–22 ISU Challenger Series. Medals were awarded in men's singles, women's singles, pair skating, and ice dance, although the men's event was not considered part of the Challenger Series due to the entry requirements not being met.

The International Skating Union published the list of entries on August 24, 2021.

Note: For this category, the 2021 Autumn Classic International was not considered a Challenger Series event, since the minimum required number of entries for a Challenger Series event was not reached.