Alaska Day is a legal holiday in the U.S. state of Alaska, observed on October 18. It is the anniversary of the formal transfer of the Territory of Alaska from Russia to the United States which took place at a flag-raising ceremony at Fort Sitka on Friday October 18, 1867 (11 hours behind St. Petersburg, Russia, half past midnight, Saturday 7 October, St. Petersburg time, Julian Calendar, or 3:30 p.m. in Sitka, 7 October).

Alaska Day is observed statewide, and is a paid holiday for State of Alaska employees. The official celebration is held in Sitka, where schools release students early, many businesses close for the day, and events such as a parade and reenactment of the flag raising are held.