The Under-18 Series is a three-game series vs. Canada that features the U.S. Under-18 Women's Select Team. Twenty-five players are chosen to represent the U.S. following participation in the USA Hockey Women's National Festival.

The Series has been held annually since 2007. The 2024 series was played in St. Catharines, Ontario in August 2024. Team USA won game three in dramatic fashion, taking a seven-round shootout to win, 4-3, but ultimately dropped the series by the 0-1-0-2 record.

Following the 2024 series, the U.S. and Canada have met 15 times, playing 45 all-time games, at the Under-18 Series and Team USA holds a 14-4-5-25 (W-OTW-OTL-L) record.